Transcript: Torque and Lever Arms ST9 | Aug 24, 1998

(music plays)

Against a starry sky with grid lines and a galaxy, a globe spins and a pink gear rotates. At the same time, another pink piece orbits around the globe. A title in yellow letters reads “A World in Motion Two.”

Missus Lorraine appears on screen. She is in her thirties, with short brown hair tied-up and bangs. She’s wearing a black jacket over a brown shirt and a silver plane brooch on her left lapel.

She says HI.
WELCOME BACK TO THE
VIRTUAL CLASSROOM.
I HOPE YOU HAD
A GREAT WEEKEND.
I KNOW I DID, BUT IT'S
NICE TO BE BACK WITH YOU.
TODAY FOR OUR CLASS, WE
WILL BE DOING AS FOLLOWS:

A slate appears on screen. It reads “Agenda: 1. Rim force of individual gears.”

She continues WHICH WAS YOUR HOMEWORK FOR
LAST WEEK, AND IF YOU DID NOT
DO IT, WE'LL BE TALKING
ABOUT THAT ANYWAY.

The slate continues “2. Torque/Lever arms. 3. Activity. 4. Homework.”

She continues NOW A LITTLE REVIEW FROM THE
LESSONS WE'VE DONE SO FAR.
I'M GOING TO TALK TO YOU
A BIT ABOUT GEAR RATIO.
I KNOW YOU'RE GETTING EXPERTS
AT THIS, I HOPE, AT THIS
POINT, BUT IF YOU LOOK AT THIS
PAPER HERE -- BRING THAT IN A
TAD -- AND LET'S SAY WE
HAVE A GEAR RATIO OF...
OR GEARS ONE...
IT'S NOT VERY CIRCULAR BUT
I'M SURE YOU CAN IMAGINE.
WE HAVE A 45-TOOTH
GEAR ATTACHED TO...
A 75-TOOTH GEAR, AND THEN
IT HAS, ON THE SAME AXLE,
A 15-TOOTH GEAR, WHICH
IS ATTACHED TO...
A 45-TOOTH GEAR, OKAY?
AND IMAGINE THAT'S ALL COVERED
UP BECAUSE OBVIOUSLY THE
GEAR'S THERE.

She draws circles as she names them.

She continues WHAT WOULD BE THE GEAR RATIO?
TRY AND FIGURE IT OUT.
I'LL GIVE YOU ABOUT 30
SECONDS, AND THEN I WILL
EXPLAIN IT FROM THERE.
ONCE YOU HAVE ANSWER, PRESS POUND 8
SO I KNOW THAT YOU ARE DONE.
OKAY, SOME OF YOU
HAVE ANSWERED.
I STILL NEED MORE.
PRESS POUND 8 ONCE YOU
HAVE AN ANSWER FOR THIS.
GOOD, THE NUMBERS
ARE GOING UP.
OKAY, HAVE A LOOK AT YOUR
SHEET, AS WELL AS WHAT I'M DOING
HERE AND SEE IF YOU WENT ABOUT
IT THE SAME WAY AS MYSELF HERE.
SO IF YOU HAVE A 45 ATTACHED
TO THE 75-TOOTH GEAR, IF YOU
THINK OF THE NUMBER 15, THIS
WILL ROTATE FIVE TIMES WHILE
YOUR 75-TOOTH GEAR WILL
ROTATE THREE TIMES, OKAY?
AND ONE WAY OF DOING THAT IS
JUST SAYING 75 OVER 45, AND IF
YOU SIMPLIFY, IT GIVES
YOU FIVE OVER THREE.
YOU HAVE TO MULTIPLY
THAT WITH THE NEXT TWO.
THE 15-TOOTH GEAR WILL GO
THREE TIMES AND THE 45 WILL
JUST GO THE ONCE, THEREFORE,
YOUR GEAR RATIO SHOULD BE 15
TO 3, BUT AS WE CAN SEE,
WE CAN SIMPLIFY THAT.
THE NUMBER 3 GOES INTO
3 ONCE, INTO 15 THREE TIMES,
THEREFORE, YOUR GEAR
RATIO IS 3 TO 1.
THE DRIVER IS GOING THREE
TIMES WHILE THE DRIVEN IS
GOING ONLY ONCE.
SO THAT SHOULD HAVE BEEN...
WHOOPS, SORRY.
THREE GOES INTO 15 FIVE TIMES.
THEREFORE, IT
SHOULD BE 5 TO 1
SO THIS HAS TO ROTATE FIVE
TIMES AND THE FINAL DRIVEN
GEAR WILL ONLY ROTATE ONCE.
OKAY?
AND I'M NOTICING
I DO HAVE A CALL.
FROM SOUTHWOOD PARK.
WHILE WE'RE WAITING FOR THAT
CALL TO CONNECT, I'M GOING TO
BE GIVING YOU ANOTHER EXAMPLE
OF THAT, BUT THIS TIME,
YOU'LL BE ANSWERING WITH
YOUR PHONES TO VERIFY
THAT YOU UNDERSTAND.
HELLO.

A boy says I WAS GOING TO TELL THE ANSWER
BUT YOU DID IT ON TV, SO...

Lorraine says OH, OKAY, THAT'S GREAT.
WELL, MAYBE I'M GOING TO
CONNECT YOU AGAIN, BUT YOU'LL
HAVE A CHANCE TO CALL IN
A FEW MINUTES BECAUSE
WE'RE GOING TO BE
DOING IT WITH THE
TELEPHONES, OKAY?
GREAT, THANKS.

The boy says BYE.

She says BYE.
SO THE NEXT ONE WHERE YOU'RE
GOING TO HAVE A CHANCE TO TRY
IT IS AS FOLLOWS:
AND I'LL BRING
THAT DOWN A TAD.
WE HAVE A 15-TOOTH GEAR
ATTACHED TO ONE OF THE LARGE
ONES, A 75, OKAY?
AND THEN ON THE SAME AXLE, YOU
HAVE A 15-TOOTH, WHICH SHOULD
BE APPROXIMATELY THE SIZE OF
THAT ONE, BUT I'M NOT DOING
TOO WELL.
AND IT IS ATTACHED TO THE 45.
NOW, YOU TELL ME...
TAKE A FEW MINUTES.
TRY AND FIGURE IT OUT, AND
THEN I WILL TELL YOU WHICH...
I'LL GIVE YOU THREE CHOICES TO
PICK FROM AND THEN WHAT I WANT
FROM THERE IS IF YOU THINK
THE ANSWER IS 1 TO 15, PRESS 3.
IF YOU THINK IT'S 3 TO 1, PRESS 2.
AND IF YOU THINK IT'S 15 TO 1,
PRESS 1.

She appears on a small window at the right bottom of the screen.

She continues AND FROM WHAT I'M SEEING,
I HAVE 40 PERCENT OF YOU
WHO HAVE ANSWERED, GOOD.
60 PERCENT.
LET'S TRY FOR 75, SO A FEW
MORE OF YOU NEED TO ANSWER.
OKAY, IF WE LOOK AT THE BAR
GRAPH, THE MAJORITY OF YOU ARE
FEELING IT IS A RATIO OF 15 TO 1,
BUT THERE ARE SOME OF YOU
THAT THINK MAYBE 3 TO 1 AND
SOME, 1 TO 15, AND I NOTICE
WE HAVE A FEW CALLS HERE.

A three-bar graph appears. A green bar reads “21,” a purple bar reads “6” and a blue bar reads “3.”

She continues I'M CALLING SOUTHWOOD
PARK ONCE AGAIN.
HELLO.

A girl says HELLO?

Lorraine says HI, WHICH ANSWER
DID YOU PICK?

The girl says NUMBER 1, 15 TO 1.

Lorraine says OKAY, AND THAT IS
THE CORRECT ANSWER.
SO THOSE OF YOU WHO CHOSE
15:1, BRAVO, AND COULD YOU
EXPLAIN TO ME WHY
YOU SAID 15:1?

The girl says THE DRIVER WILL GO AROUND 15
TIMES AND THE DRIVEN WILL ONLY
GO AROUND ONCE.

Lorraine says OKAY, CORRECT, BUT HOW
DID YOU FIGURE IT OUT?
DO IT IN LONG.

The girl says WE WENT 15...
15 TO 75 IS 5 TO 1.

Lorraine says OKAY, EXACTLY.
THIS WILL ROTATE FIVE TIMES,
AND HERE, I'LL BRING IT DOWN
LIKE THIS.
SO THE 15-TOOTH GEAR WILL
ROTATE FIVE TIMES, WHILE THE
75 ONLY ONCE.
I HAVE TO MULTIPLY,
AND WHAT...
HOW MANY TIMES WILL THE 15 GO?

The girl says THREE TIMES.

Lorraine says THREE, AND HOW MANY
TIMES WILL THE 45?

The girl says ONCE.

Lorraine says ONCE, AND YOU'RE CORRECT.
IT'S 15 TO 1, WHICH IS
THE ANSWER WE HAD HERE.
THANK YOU VERY MUCH.

The girl says OKAY, BYE.

Lorraine says BYE.
LAST WEEK AS WELL, WE SPOKE
ABOUT WHEEL RIM FORCE, AS WELL
AS THE SPEED OF OUR VEHICLES,
SOME OF THE VEHICLES THAT WE
TRIED OUT, AND ONE OF THE
PAGES THAT WE LOOKED AT -- AND
I'VE ONLY PUT A COUPLE OF
EXAMPLES HERE -- LOOK LIKE
THIS, OKAY, WHERE WE HAD A
GEAR RATIO OF 15 TO 1, AND WE
ALSO HAD A GEAR RATIO
OF 3 TO 1, AND THEN WE
ACTUALLY CLOCKED THIS PARTICULAR
GEAR RATIO ON OUR VEHICLES
TO SEE HOW FAST IT WOULD
MOVE FOR THREE METRES, OKAY?

She shows a blue piece of paper with three columns. Under the title “Gear Ratio,” the first one reads “1. 15 to 1, 2, 3, 4. 3 to 1.” Under the title “Speed (3 meters),” the second one reads “7 seconds. 2 seconds.” And under the title “Force of Wheel Rim,” the last one reads “2 and a half N. 3 and a half N.”

She continues AND THAT DISTANCE OF THREE
METRES, THE 15 TO 1, THE LARGER
GEAR RATIO, TRAVELLED
7 SECONDS, AND 3 TO 1 TRAVELLED
IN 2 SECONDS, SO IT WAS A
LOT FASTER THAN THE 15 TO 1,
THE LARGER RATIO.
NOW, WE ALSO LOOKED AT THE
FORCE OF WHEEL RIM, AND WE
NOTICED IT WAS MUCH HIGHER OF
A FORCE FOR THE LARGER RATIO,
15 TO 1, AND THEN THE WHEEL
RIM FORCE LOWERED AS THE
GEAR RATIO LOWERED.
LOOKING AT THAT -- AND YOU MAY
WANT TO WRITE THAT DOWN IF YOU
DIDN'T HAVE THAT -- I'M GOING
TO BE NOW ASKING YOU QUESTIONS
WHERE YOU HAVE TO
ANSWER WITH YOUR PHONES.
SO WHILE I'M GETTING THAT
ORGANIZED, YOU CAN BE HAVING
THIS SHEET IN FRONT OF YOU
BECAUSE I'M GOING TO TAKE IT
AWAY FROM YOU IN A MINUTE, AND
ASKING YOU A FEW QUESTIONS,
WHICH IS A REVIEW
FROM LAST WEEK.
OKAY, QUESTION NUMBER ONE, AS
SPEED INCREASES, IF YOU'RE
LOOKING AT THAT SAME
SHEET, AS SPEED INCREASES,
DOES FORCE DECREASE?
TRUE OR FALSE?

A gray bar graph goes from “0 per cent” to “70 per cent.”

She continues IF YOU THINK IT'S TRUE,
PRESS ONE; FALSE, PRESS TWO.
SO AS SPEED INCREASES,
FORCE DECREASES.
AND IF WE LOOK AT OUR BAR
CHART, WE'RE NOTICING THE
MAJORITY OF YOU HAVE SAID
TRUE, AND WE'RE NOTICING A FEW
MORE ARE ADDING ON TO THAT,
WHICH IS GREAT, AND YOU...

A two-bar graph appears. A green bar reads “32” and a purple bar reads “4.”

She continues LET'S LOOK AT THE INFORMATION.
SO WE'RE SAYING AS
SPEED INCREASES...
AND HERE'S WHERE IT'S
INCREASING, RIGHT, BECAUSE
THIS ONE TAKES A LOT LONGER TO
GET TO THE THREE METRES -- IT
TAKES SEVEN -- SO AS SPEED
INCREASES, FORCE DECREASES,
AND WE'RE CORRECT.
SO IF WE GO BACK TO THE
QUESTION, THOSE OF YOU WHO
SAID TRUE, BRAVO.
NEXT QUESTION, AND ONCE AGAIN,
LET'S LOOK AT THIS FOR A
FEW SECONDS.

She shows the table one more time.

She continues LOOKING AT THAT CHART AGAIN,
IT SAYS THE HIGHER THE GEAR
RATIO, THE HIGHER
THE WHEEL RIM FORCE.
IS THAT TRUE OR FALSE?
THE HIGHER THE GEAR RATIO, THE
HIGHER THE WHEEL RIM FORCE.
IF YOU THINK IT'S TRUE,
PRESS ONE; FALSE, PRESS TWO.
WE HAVE ABOUT 72 PERCENT OF
YOU WHO HAVE ANSWERED, AND
IF WE LOOK AT OUR BAR GRAPH...

The gray bar graph goes from “0 per cent” to “72 per cent.”

She continues WHOA, WE HAVE A REAL
MIXED FEELING THERE.
WE'RE NOT SURE.
IF WE LOOK, THE HIGHER THE
GEAR RATIO, THE HIGHER THE
WHEEL RIM FORCE.

The two-bar graph appears. The green bar reads “16” and the purple bar reads “19.”

She continues WELL, LET'S LOOK AT OUR CHART.
IT SAYS THE HIGHER THE GEAR
RATIO, WHAT ARE WE NOTICING
WITH THE WHEEL RIM FORCE?
IT'S DEFINITELY HIGHER.
OKAY, SO THOSE OF YOU...
LET'S GO BACK TO THE QUESTION
THAT SAYS THE HIGHER THE GEAR
RATIO, THE HIGHER THE WHEEL
RIM FORCE, IT IS TRUE.
SO IT'S NUMBER ONE, SO THE
16 OF YOU WHO HAVE ANSWERED
NUMBER ONE, BRAVO.
THOSE OF YOU WHO ANSWERED
FALSE, HAVE A LOOK AT YOUR
CHART AGAIN.
YOU'RE GETTING MIXED
UP WITH THE GEAR RATIO.
NOW, LOOKING AT THAT AGAIN,
I HAVE ONE MORE QUESTION,
WHICH IS STILL A REVIEW
FROM LAST WEEK.
THE QUESTION BEING, AS THE
GEAR RATIOS GET HIGHER, SPEED
BECOMES SLOWER, TRUE OR FALSE?
AS THE GEAR RATIOS GET HIGHER,
SPEEDS BECOME SLOWER,
AND LOOK AT YOUR CHART.
OKAY, WE HAVE
ABOUT 70 PERCENT.

The gray bar graph goes from “0 per cent” to “70 per cent.”

She continues I'M GOING TO QUICKLY GO INTO
THIS AND WE'RE NOTICING A
GREAT MAJORITY OF YOU
FEEL THE ANSWER IS TRUE.

The two-bar graph appears. The green bar reads “27” and the purple bar reads “8.”

She continues LET'S LOOK AT OUR PAGE HERE,
AND THE QUESTION WAS SAYING,
AS THE GEAR RATIOS GET HIGHER,
WHAT HAPPENS TO YOUR SPEED?
IT'S SLOWER.
IT TAKES SEVEN SECONDS,
WHEREAS HERE, IT WAS TAKING
ONLY TWO SECONDS.
SO IT'S CORRECT.
LOOKING BACK AT THE QUESTION,
AS THE GEAR RATIOS GET HIGHER,
SPEEDS BECOME SLOWER,
IT IS DEFINITELY TRUE,
SO GOOD FOR YOU.
AND THE REASON WHY I CHOSE
TO PUT TRUE AT ALL THREE,
ESPECIALLY WITH FALSE OR
TRUE OR MULTIPLE CHOICE IS
SOMETIMES IT'S...
PEOPLE EXPECT TO HAVE
DIFFERENT ANSWERS THERE, BUT I
PURPOSELY PUT ALL THREE TRUE
TO FORCE YOU TO HAVE TO LOOK
AT IT AND FIGURE IT
OUT, SO GOOD FOR YOU.
NOW, THIS LESSON WE...
OR FOR THE HOMEWORK OF LAST
THURSDAY, I ASKED YOU TO
MEASURE THE RIM FORCES OF
INDIVIDUAL GEARS, AND IN ORDER
TO DO THAT...
AND IF YOU DIDN'T
DO IT, MAYBE IT WOULD BE
A GOOD THING FOR YOU
TO DO SOMETIME THIS WEEK
SO YOU UNDERSTAND THIS
LESSON A TAD BETTER.
WHAT IS REQUIRED OF YOU WHEN
YOU DO THAT IS LIKE WE DID
LAST WEEK WITH THE WHEEL RIM
FORCE, THIS TIME, IT'S WITH
THE GEAR.
HERE I HAVE A 15-TOOTH GEAR
ONTO THE VEHICLE FRAME.
IT'S CONNECTED TO A STRING,
OKAY, AND IT IS THEN CONNECTED
TO THE BASE OF THE SCALE IN
NEWTONS, AND WHAT YOU DO THEN
IS THE MOTOR IS CONNECTED
TO THIS 15-GEAR.
YOU TURN ON THE MOTOR AND...
LIKE WE DID LAST WEEK WITH THE
WHEEL RIM FORCE, AND THEN YOU
WERE TO CHECK THE
NEWTONS AND...
FORCE WITH THE DIFFERENT
INDIVIDUAL GEARS.

She shows the drawing she’s describing.

She continues WHAT I'D LIKE FROM YOU
IS TO TELL ME THE RESULTS
THAT YOU RECEIVED.
SO IF YOU CAN CALL ME BY
PRESSING POUND 9 AND LET ME KNOW,
WHAT WAS THE APPROXIMATE
FORCE IN NEWTONS THAT YOU HAD
FOR THE 15-TOOTH GEAR,
THE 45 AND THE 75?
AND WE HAVE A FEW CALLS.
HELLO.

A female student says HI.

Lorraine says HI.
WHAT DID YOU GET AS AN ANSWER
HERE FOR EITHER THE 15,
THE 45 OR THE 75-TOOTH?

The female student says FOR THE 15-TOOTH GEAR,
I GOT 0.65 NEWTONS.

Lorraine says WOW, YOU'RE RIGHT ON.
THAT'S EXCELLENT.
GOOD FOR YOU.

Lorraine covers the answer with a piece of paper and when the female student replies Lorraine uncovers it.

Lorraine continues AND I ALSO PUT IT IN GRAMS,
BUT ONE DOESN'T HAVE TO IN
CASE YOU ONLY HAD THE SCALE
FOR THAT, BUT THANK YOU
VERY MUCH.

The female student says YOU'RE WELCOME.

Lorraine says BYE.
AND LET ME TRY HERE...
HELLO.

A schoolgirl says HELLO.

Lorraine says HI.
AND WHAT DID YOU GET
FOR THE 45-TOOTH?

The schoolgirl says I GOT 0.25 NEWTONS.

Lorraine says 0.25, EXACTLY
WHAT I RECEIVED.
THANK YOU.
EXCELLENT.
AND LET'S TRY...
HELLO.

A female teenager says HELLO?

Lorraine says HI.
WHAT DID YOU GET FOR 75-TOOTH?

The female teenager says WE GOT 0.15 NEWTONS.

Lorraine says 0.15, EXCELLENT.
WELL, THANKS VERY MUCH.
THE SAME NUMBERS
THAT I RECEIVED.
GREAT.

The female teenager says OKAY, BYE.

Lorraine says BYE.
NOW, IF I WERE TO PUT THIS
INFORMATION ON TO A GRAPH,
OKAY, AND I'M PURPOSELY GOING
TO HIDE MY RESULTS OF MY GRAPH
HERE, SO IMAGINE THESE LINES
GOING RIGHT ACROSS, OKAY, AND
ON THIS SIDE, I HAVE NUMBER
OF TEETH FOR THE GEARS, SO WE
HAVE THE 15, THE 45, WHICH
WOULD BE ABOUT THERE, AND THE
75, AND THEN WE HAVE THE
DIFFERENT FORCES IN NEWTONS.
CALL ME BY PRESSING POUND 9 AND
TELL ME WHERE WOULD I PUT THE
DOT HERE TO SHOW THE AMOUNT
OF FORCE TO MY 15-TOOTH GEAR.
SO PRESS POUND 9 AND TELL ME
WHERE ON THAT GRAPH I WOULD
PUT THE ANSWER FOR THAT.
AND WE'RE CALLING
SOUTHWOOD PARK.
HELLO.

A male adolescent says HI.

Lorraine says HI, AND WHERE APPROXIMATELY
WOULD I GO MORE TO THE LEFT?
IF I'M IN THE CENTRE, RIGHT
APPROXIMATELY HERE,
WHERE SHOULD I PUT, FOR
THE 15-TOOTH GEAR?

The male adolescent says RIGHT ON THE .6

Lorraine says OKAY, RIGHT AT THE.6, AND HOW...

The male adolescent says JUST A BIT AFTER IT.

Lorraine says OKAY, AND A LITTLE
BIT AFTER IT.
WHY IS THAT?

The male adolescent says BECAUSE IT WAS .65.

Lorraine says VERY GOOD, IT WAS .65,
AND WHERE DO I GO OVER
HERE AS FAR AS HOW MANY
TEETH FOR THE 15?

The male adolescent says RIGHT IN THE MIDDLE
BETWEEN 10 AND 20.

Lorraine says THAT'S RIGHT, SO I HAVE TO
JOIN THEM, SO I COME RIGHT
ACROSS AND LET'S SEE IF
THAT'S WHERE I HAD IT.
THAT'S ABOUT EXACTLY
WHERE YOU SAID.
DO YOU WANT TO HELP ME
NOW FOR THE 45-TOOTH?

The male adolescent says OKAY.

Lorraine says WHERE WOULD I GO HERE?
WHERE'S 45?

The male adolescent says BETWEEN 40 AND 50.

Lorraine says OKAY, GREAT.
AND NOW WHAT WAS THE RESULTS
IN FORCES, IN NEWTONS FOR THAT?

The male adolescent says.25

Lorraine says .25, SO WHERE
WOULD THAT BE?

The male adolescent says JUST A BIT AFTER THE .2

Lorraine says YEAH, IT SHOULD BE
RIGHT AROUND HERE THEN.
SO WE GO THERE AND WE CONNECT
WITH THE 45 AND THOSE TWO JOIN
UP, SHOULD BE...
LET'S SEE IF THAT'S
WHAT WE HAVE.
YES, VERY GOOD.
NOW, HOW ABOUT THE 75-TOOTH?

The male adolescent says IT'S BETWEEN THE
70 AND THE 80.

Lorraine says OKAY, GOOD.

The male adolescent says AND YOU WOULD PUT IT,
WELL, LIKE HALFWAY...
RIGHT UP...
HALFWAY BETWEEN
THE ZERO AND THE .2

Lorraine says OKAY, AND LET'S SEE.
THAT'S APPROXIMATELY, BECAUSE
WHAT WAS THE ANSWER THERE?

The male adolescent says.15

Lorraine YEAH, .15, LIKE, ONE WOULD BE
RIGHT IN THE MIDDLE HERE,
SO IT'S BETWEEN THE ONE AND...
SO ABOUT THREE QUARTERS OF THE
WAY, AND THAT'S WHAT WE SEE.
GREAT, AND THANKS VERY MUCH.

The male adolescent says YOU'RE WELCOME.

Lorraine says NOW, IF WE LOOK AT THAT ONE
MORE TIME AND TRY AND
IMAGINE WHAT WE'RE TALKING
ABOUT, AND IT'S THE RIM FORCE
FROM THE TEETH OF THE
GEARS, AND AS WE CAN SEE
FROM THIS GRAPH, THAT THE
PRODUCT IS VERY CLOSE FOR THE
THREE GEARS, INDICATING THAT
THE TORQUE TRANSMITTED BY THE
MOTOR IS ABOUT THE SAME
FOR ALL THREE GEARS.
WELL, WHAT IS TORQUE?
WELL, LET'S LOOK HERE.
TORQUE IS A RATIONAL --
ROTATIONAL
FORCE.
AN EXAMPLE FROM THAT IS FROM
THE MOTOR SHAFT TO THE GEAR,
AND AS WE ALL KNOW, THE SHAFT
FROM THE MOTOR ROTATES VERY,
VERY QUICKLY AND WILL
OBVIOUSLY ROTATE WHATEVER
GEAR YOU HAVE ON IT, AND
THAT FORCE THAT'S ROTATING
LIKE THAT IS THE TORQUE, OKAY?
AND I HAVE A LITTLE VIDEO
FOR YOU TO VISUALIZE AND
UNDERSTAND TORQUE A
LITTLE BIT BETTER.

A clip plays.

Andrew Marquette stands in a mechanics workshop. He’s in his late thirties, clean-shaven with long brown hair. He’s wearing a green T-shirt with a motif and blue jeans.

Andrew says THE TERM TORQUE,
ESPECIALLY TO SOMEONE WHO
DOESN'T UNDERSTAND ENGINES,
IT REALLY IMPRESSES THEM,
PROBABLY BECAUSE THEY DON'T
UNDERSTAND WHAT IT MEANS.
SO IF YOU WANT TO IMPRESS
PEOPLE AS WELL, STICK WITH ME
AND I'M GOING TO TELL YOU
WHAT THE TERM TORQUE MEANS.
TORQUE IS SIMPLY A TWISTING
OR A TURNING FORCE.
NOW, I'M GOING TO GIVE
YOU JUST A BRIEF EXAMPLE.
WAIT'LL I MOVE MY ENGINE HERE.
I'M GOING TO GIVE
YOU A BRIEF EXAMPLE.
WATCH THIS CRANK SHAFT
AND WHAT HAPPENS TO IT.
SURE, YOU CAN SEE THAT.
IT'S TURNING.
IT'S DEVELOPING TORQUE.
NOW, WE CAN MEASURE TORQUE,
BUT FIRST, I'M GOING TO...
BEFORE WE MEASURE TORQUE, I
WANT TO SHOW YOU WHAT HAPPENS
WHEN WE APPLY TOO MUCH
TORQUE TO SOMETHING.
GOT A WRENCH HERE,
GOT A BOLT IN HERE.
NOW, I'M GOING
TO JUST TURN IT.
OOH, THERE IS GOES.
SEE WHAT HAPPENS THERE?
WHAT HAPPENED THERE WAS I TOOK
AND I TORQUED A BOLT, AND
I TORQUED IT TOO MUCH.
I PUT TOO MUCH TWISTING FORCE
ON IT TO THE POINT WHERE IT
ACTUALLY BROKE.
NOW, TO PREVENT THAT FROM
HAPPENING, IF I WANT TO TAKE
AND KNOW EXACTLY HOW MUCH
TORQUE OR TWISTING FORCE TO
PUT ON A BOLT, FOR EXAMPLE,
I CAN USE A TORQUE WRENCH
LIKE THIS ONE.
NOW, YOU NOTICE IN THIS TORQUE
WRENCH I'VE GOT A SERIES OF
NUMBERS ON THE TORQUE WRENCH?

A close-up shot of the torque wrench appears.

Andrew continues THAT'S TO TELL ME EXACTLY
HOW MUCH TORQUE I APPLY
TO SOMETHING.
NOW REMEMBER, TORQUE
CAN BE MEASURED.
TORQUE CAN BE MEASURED IN
NEWTON METRES OR IT CAN BE
MEASURED IN FOOT POUNDS.
SO IT'S VERY IMPORTANT THAT
YOU REMEMBER TORQUE IS SIMPLY
A TWISTING FORCE.
NOW REMEMBER, IF WE PUT TOO
MUCH TORQUE ON SOMETHING,
A BOLT WILL BREAK.
OKAY?
SO THAT'S WHAT CAN HAPPEN IN A
SMALL ENGINE IF WE DON'T USE A
TORQUE WRENCH WHEN WE'RE
TIGHTENING BOLTS DOWN,
FOR EXAMPLE.
WE COULD OVER-TORQUE THEM.

The clip ends.

Back in the studio, Lorraine says NOW, THAT WAS EXPLAINED
BY ANDREW MARQUETTE AT
ABRAM LAKE, WHICH
IS UP NORTH FROM...
NORTHERN ONTARIO, AND I HAVE
HERE AS WELL A TORQUE WRENCH
WHICH I WILL BE TALKING TO YOU
IN APPROXIMATELY A FEW MINUTES
AND EXPLAINING MY TORQUE
WRENCH, WHICH IS SLIGHTLY
DIFFERENT THAN THE ONE YOU
SAW FROM ANDREW MARQUETTE.
BUT THE MAIN LESSON TODAY IS
ABOUT TORQUE AND RELATING IT
WITH THE LEVER
ARM LENGTH, OKAY?
AND AN EXPLANATION OF LEVER
ARM, AND IT CAN BE A LITTLE
BIT CONFUSING, PROBABLY THE
EASIEST WAY WOULD BE AS
FOLLOWS: HERE, YOU SEE
REVOLVING DOORS, OKAY?
THESE ARE DOORS AND
THIS IS THE PERSON.
WE'RE SEEING IT FROM ABOVE,
AND THE PERSON IS TRYING TO
GO THROUGH THE REVOLVING
DOORS TO GET OUT IN ANY
PARTICULAR SECTION.

She grabs a new piece of paper that features two drawings.

She continues AND IF YOU'VE NEVER BEEN IN
A REVOLVING DOOR, WELL JUST
IMAGINE THIS BEING A DOOR AND
YOU'RE STANDING RIGHT DIRECTLY
IN FRONT OF IT, OKAY, AND
WE'RE LOOKING AT YOU ON TOP
THERE, AN AERIAL VIEW.
NOW, WITH THIS, TO TURN A
REVOLVING DOOR, YOU PUSH ON
THE DOOR WITH YOUR ARM TO MAKE
THE DOOR ROTATE AROUND THE
PIVOT POINT OF
ITS CENTRE, RIGHT?
IT'S GOT TO ROTATE FROM THIS
PIVOT POINT IN THE CENTRE.
IF YOU PUSH AT THE OUTER EDGE,
LIKE THIS PARTICULAR PERSON'S
DOING -- SEE THEIR HAND?
THEY'RE AT THE OUTER EDGE OF
IT -- YOU NEED TO PUSH WITH
LESS FORCE THAN IF YOU PUSH
AT THE NEAR EDGE OF THE PIVOT
POINT, AND YOU MIGHT WANT TO
TRY THIS JUST WITH A REGULAR
DOOR AT ONE POINT.
IF YOU TRY CLOSING
OR OPENING A DOOR
FROM RIGHT NEAR THE HINGE
SECTION, IT'S VERY, VERY
DIFFICULT TO DO.
WELL, NOT... BUT A LOT MORE
DIFFICULT THAN IF YOU WERE
TO TRY IT AT THE OUTER
EDGE OVER HERE, OKAY?
SO IF YOU HAVE A CHANCE TO TRY
THAT, THAT WOULD BE GREAT.
NOW, AS WELL, IF YOU
WERE TO LOOK AT...
IF YOU WERE TO IMAGINE HERE
YOUR GEAR, IT'S VERY SIMILAR
TO THE REVOLVING DOORS.
IT'S LIKE A SPOKED WHEEL, YOU
KNOW, ON YOUR BIKE AND SO ON,
IF YOU WANTED TO IMAGINE THAT,
AND WITH THE LEVER ARMS JUST
EXTENDING OUT A BIT, JUST LIKE
OUR GEARS THAT WE SEE, OUR
SPUR GEARS, THERE'S LITTLE
SECTIONS STICKING OUT.
BUT TRY AND IMAGINE FOR EACH
SECTION STICKING OUT, THERE'S
A LEVER ARM, AND THE TIPS OF
EACH SPOKE STICK OUT AND SERVE
AS A LEVER ARM, AS YOU
CAN TELL HERE, AND IT NOW
RESEMBLES A GEAR THAT WE'RE
FAMILIAR WITH, AND FROM THIS,
IF YOU MULTIPLY...
LIKE TO FIGURE OUT TORQUE,
WHICH IS VERY IMPORTANT...
AND I WILL EXTEND
THAT OUT A TAD.
TO FIGURE OUT TORQUE -- AND
YOU SHOULD PROBABLY WRITE THIS
DOWN -- YOU NEED TO MULTIPLY
FORCE, WHICH WE ALREADY KNOW
IS IN NEWTONS, TIMES -- SO IT'S
THE PRODUCT OF FORCE -- TIMES
THE LEVER ARM, THE
LENGTH OF THE LEVER ARM.
OKAY?
AND IT IS IN METRES.
SO YOUR FULL ANSWER FOR TORQUE
IS THE PRODUCT OF FORCE TIMES
THE LEVER ARM, SO IT WILL BE
IN NEWTON METRES, AND NEWTON
WILL ALWAYS TAKE A CAPITAL
N AND METRES, A SMALLER M.
OKAY?

As she speaks, she writes down the ecuation.

She continues SO DEPENDING ON THE SIZE OF
YOUR GEAR, IF YOU HAVE JUST
THE 15, OBVIOUSLY IT'LL BE
MUCH SMALLER IN DIAMETER
THAN YOU WOULD WITH
THE LARGER GEARS.
NOW, YOU'RE GOING TO HAVE AN
ACTIVITY TO DO, WHICH IS
THE FUN PART.
AND YOU'RE GOING TO NEED, AS
WAS MENTIONED IN THE SLATE
WITH THE MATERIALS, YOU'RE
GOING TO NEED A RULER THAT
ACTUALLY SHOWS
MILLIMETRES, OKAY?
AND FOR THIS ACTIVITY, YOU'RE
GOING TO HAVE YOUR GEARS IN
FRONT OF YOU, THE 15, THE
45 AND THE 75, AND AS WELL,
WHAT'S GOING TO BE
REQUIRED FROM YOU IS...
A DATA SHEET THAT LOOKS LIKE
THIS, AND SO IF YOU DON'T
HAVE ONE, I WOULD LIKE YOU TO
WRITE THIS INFORMATION DOWN SO
THAT YOUR ACTIVITY
IS THAT MUCH SIMPLER.

She grabs a blue piece of paper that shows a five-column table under the title “Torque Calculation Table.”

She continues SO FROM THIS ACTIVITY, YOU
HAVE YOUR 15, YOUR 45 AND YOUR
75, AND YOU CAN JUST DRAW IT
OR WRITE THE NUMBERS DOWN.

She points to the first column that shows three circles of different sizes. The first one reads “15,” the second and larger one reads “45,” and the last and much bigger one reads “75.”

She continues YOU'RE GOING TO PUT DOWN --
AND I'LL BRING THAT IN JUST A
TAD -- YOU'RE GOING TO HAVE TO
TELL ME THE FORCE IN NEWTONS,
AND YOU'VE ALREADY GIVEN THAT TO
ME TODAY SO YOU KNOW THE FORCE
IN NEWTONS FOR ALL THREE AND
WE EVEN DID A DATA GRAPH AND
SO ON FOR THAT.
AS WELL, YOU'RE GOING TO HAVE
TO GIVE ME YOUR LEVER ARM
LENGTH, SO IT'S RIGHT
FROM THE CENTRE, OKAY?
LET ME DO THE LARGER ONE,
WHICH IS A LITTLE BIT EASIER.
RIGHT FROM THE CENTRE,
YOU'RE GOING TO MEASURE THIS
DISTANCE, CENTRE TO HERE,
TELL ME HOW MANY MILLIMETRES
FOR ALL THREE.
NOW, NOTE IT SAYS MILLIMETRES.
THEN YOU HAVE TO CHANGE THAT
TO METRES, AND THAT'S WHERE
I'M GOING TO JUST HAVE YOU TRY
AND FIGURE OUT ON YOUR OWN
AND THEN I'LL
EXPLAIN IT TO YOU.
IT'S A NICE
MATHEMATICAL QUESTION.
THEN, IN ORDER TO FIND THE
TORQUE, WHICH IS THE MAIN IDEA
HERE, YOU HAVE TO COMBINE THE
FORCE TIMES THE LEVER ARM,
WHICH WILL GIVE YOU THE ANSWER
IN NEWTON METRES, OKAY?
AND I'M GOING TO GIVE YOU
APPROXIMATELY 10 MINUTES TO DO
THAT, SO IF YOU LOOK -- 8-10
MINUTES -- I WILL EXPLAIN
TO YOU THE ACTIVITY.

The slate changes to “Calculate the torque for all three individual gears. Example: torque equals force (Newtons) times lever arm (meters).”

She continues AND THE KEY HERE, AND BE
VERY CAREFUL, IS THAT YOU'RE
STARTING OFF WITH
MILLIMETRES AND THEN YOU
GOT TO CHANGE IT TO METRES.
SO NOW YOU HAVE APPROXIMATELY
8-10 MINUTES, AND IF YOU HAVE
ANY QUESTIONS DURING THIS
TIME, PLEASE FEEL FREE
TO PRESS POUND 9.
HAVE FUN.
HELLO?

A girl says HI.

Lorraine says DO YOU HAVE A QUESTION?

The girl says NO.

Lorraine says OH, BECAUSE YOUR
PHONE RANG HERE.
OKAY, THANKS.

The girl says BYE.

Lorraine says DO YOU UNDERSTAND
THE EXERCISE?

The girl says WHAT?

Lorraine says DO YOU UNDERSTAND
THE EXERCISE?

The girl says NO.

Lorraine says NO.
DO YOU HAVE A RULER
THERE WITH YOU?

The girl says OH, YEAH.

Lorraine says AND DO YOU HAVE YOUR
GEARS IN FRONT OF YOU?

The girl says YES.

Lorraine says NOW, DO YOU KNOW HOW TO
MEASURE FROM THE CENTRE OF THE
GEARS, LIKE RIGHT HERE, WHERE
YOU HAVE TO CENTRE AND THEN
MEASURE THIS DISTANCE,
AND THEN YOU'LL PUT IT IN
MILLIMETRES OVER HERE, OKAY?

The girl says OKAY.

Lorraine says AND THEN YOU HAVE TO CHANGE
THE MILLIMETERS TO METRES.
DO YOU KNOW HOW TO DO THAT?

The girl says UM... YES.

Lorraine says OKAY, WHAT DO YOU
HAVE TO DIVIDE IT BY?

The girl says BY THE LEVER ARM.

Lorraine says OKAY, BUT YOU HAVE TO DIVIDE
YOUR MILLIMETRE ANSWER HERE TO
WHAT IN ORDER TO CHANGE IT TO
METRES, MILLIMETRES TO METRES?
YOU HAVE TO DIVIDE BY?

The girl says THE FOUR?

Lorraine says ONE.
IT'S A NUMBER.
YOU'RE JUST CHANGING
LEVER ARM TO LEVER ARM.
IT'S THE SAME THING BUT YOU'RE
JUST CHANGING MILLIMETRES
TO METRES.
HOW DO YOU CHANGE THAT?
YOU HAVE TO DIVIDE THIS
NUMBER, WHATEVER YOU GET,
BY HOW MUCH?
HOW MANY MILLIMETRES IN
A METRE, DO YOU KNOW?

The girl says A HUNDRED.

Lorraine says LITTLE BIT MORE THAN THAT.
ADD ANOTHER ZERO.

The girl says A THOUSAND.

Lorraine says THAT'S RIGHT.
SO WHATEVER NUMBER YOU'RE
GOING TO GET HERE, DIVIDE IT
BY 1,000 AND THAT WILL BE YOUR
ANSWER HERE, AND THEN IN ORDER
TO GET THIS ANSWER, YOU GOT TO
MULTIPLY THIS BY THIS, OKAY?

Lorraine shows the “Torque Calculation Table.” First, she points to the “Lever Arm (millimetres)” column and then to the “Lever Arm (metres) column.” Next, she points to the “Force Times the Lever Arm” column, the “Force in Newtons” column and finally to the “Lever Arm (metres)” column.

The girl says YEAH.

Lorraine says OKAY, HAVE FUN.

After a few minutes, Lorraine says HI.
NOW I WANT TO HEAR YOUR
ANSWERS FROM YOUR ACTIVITY,
SO ALL OF YOU SHOULD HAVE YOUR
PAGE LIKE THIS IN FRONT OF
YOU, OR SIMILAR TO IT, WHERE
YOU CAN GIVE US YOUR ANSWERS.
SO PRESS POUND NINE TO SHARE
WITH US WHAT YOU HAVE FOR
YOUR ANSWERS HERE.
HELLO.
HI.
HELLO.

A female adolescent says HELLO?

Lorraine says HI.
AND WHAT DO YOU HAVE HERE
FOR THE FORCE IN NEWTONS?
WE'VE ALREADY
TALKED ABOUT THIS.

The female adolescent says WE HAVE .65

Lorraine says OKAY, AND WE KNEW
THAT ALREADY, SO 0.65.
AND WHAT DID YOU GET FOR YOUR
LEVER ARMS IN MILLIMETRES?

The female adolescent says 9 MILLIMETRES.

Lorraine writes the caller’s answers.

Lorraine says GREAT.
AND HOW DO YOU CHANGE
THAT TO MILLIMETRES?
WHAT DO YOU HAVE TO DIVIDE BY?

The female adolescent says DIVIDE BY 1,000.

Lorraine says THAT'S RIGHT.
IF YOU THINK OF YOUR
DECIMAL HERE, HOW MANY...
IT'LL BE THEN DECIMAL...
HOW MANY ZEROES
BEFORE THE 9?

The female adolescent says TWO.

Lorraine says THAT'S RIGHT.
SO IT'S .009 METRES, AND THEN
WHEN WE'RE TALKING ABOUT
FORCE TIMES THE LEVER ARM, WHAT
DID YOU GET FOR NEWTON METRES?

The female adolescent says WE... 0.00585.

Lorraine says PERFECT.
SO WHAT YOU'VE DONE THEN IS
MULTIPLIED THESE TWO NUMBERS.

The female adolescent says YUP.

Lorraine says AND THAT GAVE YOU -- AND
I'LL HAVE TO GO OFF MY PAGE
A BIT HERE -- 0.0058 AND WE'LL
PUT HERE A BIG N AND AN M
FOR NEWTON METRES.
THAT'S WHAT YOU RECEIVED?

The female adolescent says YEAH.

Lorraine says GREAT.
WELL, THANKS VERY MUCH.

The female adolescent says OKAY, BYE.

Lorraine says BYE.
AND LET'S GET A CALL HERE FROM
SAINT CHARLES TO EXPLAIN TO US 45.
HELLO.

A schoolgirl says HI.

Lorraine says HI, AND WHAT DID YOU GET HERE
FOR FORCE FOR THE 45 GEAR?

The schoolgirl says 0.25.

Lorraine says 0.25, EXCELLENT,
IN NEWTONS, AND NOW
THE LEVER ARM IN MILLIMETRES.

The schoolgirl says 22 MILLIMETRES?

Lorraine says OKAY, I GOT A LITTLE BIT MORE
THAN THAT, BUT THAT'S OKAY.
SO WE'LL PUT 22.
I HAD 24, BUT IF WE GO BACK TO
THE CHART HERE, WHAT DO YOU
HAVE FOR THE... IN METRES?

The schoolgirl says 0.022

Lorraine says OKAY, 0.022, VERY GOOD,
BECAUSE THE DECIMAL HAS
TO GO THREE TIMES.
AND WHAT DO WE GET HERE WHEN
WE MULTIPLY THE FORCE,
WHICH IS THIS, TIMES
LEVER ARM IN METRES?

The schoolgirl says 5.5?
OH, ZERO DECIMAL.

Lorraine says WHAT DID YOU GET?
ZERO DECIMAL...

The schoolgirl says 0055

Lorraine says OKAY, 55.
WHOOPS.
WHEREAS I HAD A LITTLE BIT
MORE THAN THAT, WHERE IT WAS
60, BUT THAT'S FINE,
AND NEWTON METRES.
GREAT, THANKS VERY MUCH.
AND HOW ABOUT FOR THE THIRD
ONE HERE, LET'S TRY JACK MINER.
HELLO.

A boy says HELLO?

Lorraine says HI.
WHAT DID YOU GET FOR
THE FORCE HERE FOR 75?

The boy says I DIDN'T DO THAT ONE.

Lorraine says DO YOU REMEMBER RIGHT AT THE
BEGINNING, WE TALKED ABOUT IT?
DO YOU REMEMBER THE FORCE?

The boy says 0.15

Lorraine says PERFECT.
AND DO YOU HAVE
IT IN MILLIMETRES?
DO YOU WANT TO
TRY IT RIGHT NOW?
APPROXIMATELY WHAT IS IT?

The boy says 3.6

Lorraine says IN MILLIMETRES?

The boy says OR 36.

Lorraine says YEAH, OKAY.
WELL, I HAVE ABOUT
39, SO WE'LL PUT...
SINCE I HAVE THE RESULTS HERE,
IT'LL PROBABLY BE HELPFUL
IF WE PUT MINE.
HOW DO YOU CHANGE
THIS NOW INTO METRES?
FROM MILLIMETRES INTO
METRES, DO YOU SEE...

The boy says IT'LL BE 00.039

Lorraine says THAT'S RIGHT, 39.
AND NOW I'LL HELP YOU OUT HERE
UNLESS YOU HAVE A CALCULATOR.
DO YOU HAVE A CALCULATOR?

The boy says YES.

Lorraine says OKAY, MULTIPLY THE FORCE
TIMES THE LEVER ARM IN METRES,
AND WHAT DO YOU GET?

The boy says 0.00585

Lorraine says THAT'S RIGHT, SO
WE COULD PUT 5-9.
NOW THAT I HAVE YOU ON THE
LINE, WHAT ARE YOU NOTICING
ABOUT THE TORQUE
FOR ALL THREE GEARS?

The boy says THEY'RE ALL IN THE
FIFTIES OR IN THE FIVES.

Lorraine says YEAH, THEY'RE ALL VERY, VERY
SIMILAR AMOUNTS OF TORQUE.
EXCELLENT.
THANKS VERY MUCH.

The boy says OKAY.

Lorraine says SO WHAT THAT MENTIONING IS
WHEN YOU HAVE YOUR MOTOR AND
YOU HAVE A PARTICULAR GEAR
JUST ON THE MOTOR, IT'S THE
SAME TORQUE BEING GIVEN TO ALL
THE GEARS, BUT ONCE THEY ARE
ATTACHED TO A DRIVEN GEAR,
THEN THEIR LEVER ARMS WILL
HAVE A DIFFERENT EFFECT, OKAY?
AND LET'S WATCH A VIDEO ON
THAT TO EXPLAIN A LITTLE BIT
CLEARER ABOUT THE LEVER, AND
THEN WE'LL TALK ABOUT THAT.

A clip plays.

A slate appears on screen. It reads “The Screw and the Wheel.”

A Male Narrator says HOW MANY DIFFERENT TYPES OF
SIMPLE MACHINE DO YOU THINK
THERE ARE?
TWO.

An animation shows a male cartoon thinking while numbers float.

The Narrator continues THERE ARE ONLY TWO BASIC
MACHINES -- THE INCLINED
PLANE AND THE LEVER.
THESE ARE THE MOTHER AND
FATHER OF EVERY MACHINE
IN THE WORLD.
ALL THE OTHERS ARE MERELY
VARIATIONS ON THE SAME THEME.
FOR EXAMPLE, THERE'S
A BEAUTIFUL MACHINE.
NO, NOT YOUR CAR.
THE ROAD.

The cartoon rides a car.
The Cartoon says WHAT?

The Narrator continues YES, THE ROAD.
A WINDING MOUNTAIN
ROAD IS A MACHINE, TOO.

The Cartoon says HUH?

The Narrator says WELL, SUPPOSE THE
ROAD DIDN'T WIND.
SUPPOSE IT WENT STRAIGHT UP
THE SIDE OF THE MOUNTAIN.
THIS IS A MUCH SHORTER
WAY TO THE TOP, ISN'T IT?
AND YET, IT WON'T DO YOU
MUCH GOOD BECAUSE THE ENGINE
OF EVEN YOUR MAGNIFICENT
AUTOMOBILE HASN'T
ENOUGH FORCE TO LIFT
YOUR CAR STRAIGHT UP.
BUT SUPPOSE WE MAKE THE ROAD
LONG ENOUGH AND THE SLOPE
GENTLE ENOUGH FOR YOU TO DRIVE
UP THE MOUNTAIN WITH EASE.
WHAT HAVE WE DONE NOW?
YES, WE'VE MADE THE ROAD
INTO AN INCLINED PLANE,
A SIMPLE MACHINE.
BUT THAT'S AN EXPENSIVE
WAY TO GO UP A MOUNTAIN.

The Cartoon says MM-HMM.

The Narrator says IT REQUIRES AN
AWFULLY LONG RAMP.
WHAT IF WE WRAP
THE INCLINED PLANE
ROUND THE MOUNTAIN INSTEAD?
NOW WE'RE BACK WHERE WE
STARTED, WITH A WINDING
MOUNTAIN ROAD, WHICH IS REALLY
AN INCLINED PLANE IN DISGUISE,
A TWISTED INCLINED
PLANE, IF YOU LIKE.
THERE ARE TWISTED, INCLINED
PLANES ALL OVER THE PLACE.
THIS INCLUDES EVERY DEVICE
THAT HAS A SPIRALING
CORKSCREWING ACTION AND WHICH
ALLOWS YOU TO TRADE EXTRA
TURNING DISTANCE FOR REDUCED
FORCE, EITHER TO HELP YOU LIFT
THINGS OR FASTEN
THINGS TOGETHER.

A corkscrew spins, an hydraulic jack lifts a car and a device fastens two yellow pieces.

The Narrator continues HERE IS THE COMMONEST EXAMPLE
OF ALL, THE SCREW, WHICH IS,
IN FACT, THE VERY NAME WHICH
PHYSICISTS GIVE TO EVERY TYPE
OF TWISTED INCLINED
PLANE, THE SCREW.
SO THAT'S ONE OF THE
DESCENDENTS OF THE
INCLINED PLANE.

The Cartoon waves and wants to open a door.

The Narrator continues HANG ON A MINUTE.
CAN YOU GIVE ME AN EXAMPLE
OF A SIMPLE MACHINE THAT HAS
DESCENDED FROM THE LEVER?
WELL, YOU'RE HOLDING ONE
IN YOUR HAND RIGHT NOW.

The Cartoon says OH.

The Narrator continues YET ANOTHER MACHINE THAT
DOESN'T LOOK LIKE A MACHINE.

The Cartoon says HMM.

The Narrator continues I KNOW.
BUT HAVE YOU EVER TRIED TO
OPEN A DOOR WITHOUT A DOORKNOB?
YOU HAVEN'T GOT ENOUGH
LEVERAGE, HAVE YOU?
THAT'S WHERE THE
DOORKNOB COMES IN.
IT'S A DIRECT DESCENDANT
OF THE LEVER, LIKE THIS...
OR THIS...
OR THIS.

The Cartoon drives a car, controls the rudder of a ship and winds a rope around a capstan.

The Narrator continues THEY'RE ALL CHILDREN
OF THE LEVER.
HOW COME?
WELL, A LONG TIME AGO, SOME
VERY WISE MEN WERE LOOKING AT
A LEVER ONE DAY WHEN THEY
SUDDENLY THOUGHT HOW NICE IT
WOULD BE IF THE EXTRA FORCE
THE LEVER GIVES YOU TO MOVE
SOMETHING FROM HERE TO HERE,
SAY FOUR TIMES THE FORCE,
BECAUSE ONE LEVER ARM IS FOUR
TIMES THE LENGTH OF THE OTHER,
THEY WONDERED IF THIS EXTRA
FORCE COULD BE EXTENDED
THROUGH 360 DEGREES.
IN OTHER WORDS, THEY WONDERED
IF THEY COULD MAKE A CIRCULAR
LEVER, A LEVER THAT WOULD
GO ALL THE WAY ROUND.
AND WHILE THEY WERE AT IT,
THEY MADE UP A NEW NAME, AN
AXLE, WITH A CENTRE WHERE THE
POINT OF THE FULCRUM USED TO
BE AND THE SHORT ARM OF THE
LEVER NOW RUNNING FROM THE
CENTRE TO THE OUTSIDE OF THE
AXLE AND THE LONG ARM RUNNING
FROM THE CENTRE OF THE AXLE
IN THE OPPOSITE DIRECTION.
NOW WHEN YOU PUSH THE LEVER
WITH A FORCE, SAY OF 100
NEWTONS, YOU CAN TURN THE
WHOLE AXLE AROUND WITH A FORCE
OF 400 NEWTONS, AND THAT'S HOW
YOU'RE ABLE TO OPEN DOORS AND
STEER CARS AND SHIPS AND PULL
UP ANCHORS WITH SUCH EASE,
THANKS TO THE ANCIENT WISE
MEN AND THEIR CIRCULAR LEVER.

An animation show what the narrator describes.

A caption reads “The Circular Lever.” When the cartoon snaps his fingers, the caption changes to “The Wheel.”

The Narrator concludes YES, CONGRATULATIONS!
YOU'VE JUST
REINVENTED THE WHEEL.

(music plays)

The end credits roll.

The clip ends.

Lorraine continues AND THAT'S FROM THE EUREKA
SERIES WITH TV ONTARIO.
NOW, IF WE GO BACK TO THE
EXPLANATION OF WHAT WE SAID
WITH THE 15, 45 AND 75-TOOTH
GEAR, IF YOU IMAGINE WHAT
THEY'VE JUST SAID IN THE
VIDEO AS WELL, THE LARGER THE
STEERING WHEEL, LET'S SAY, THE
EASIER IT IS TO MOVE AROUND.
SO IF THIS, THE 75-TOOTH GEAR,
LET'S SAY, TRANSMITS THE
SMALLEST FORCE AS A DRIVER
GEAR, SO IF IT'S ON THE DRIVER
GEAR, YOU CAN IMAGINE, YOU CAN
STOP IT MUCH QUICKER THAN THIS
LITTLE 15 ONE.
JUST THINK OF THE DOOR HANDLE,
IF YOU TOOK OFF THE HANDLE
PART, IT'S MUCH SMALLER.
SO IT GIVES...
AS A DRIVER GEAR, IT GIVES
MUCH MORE FORCE THAN THE
LARGER ONE, AND THAT'S WHY
YOU'LL NOTE WHEN WE TALK ABOUT
THE GEAR TRAINS, IT'S PROBABLY
BEST IF YOU START OFF YOUR
GEAR TRAIN USING THE MUCH
SMALLER, THE 15 GEAR ON THE
SHAFT OF THE MOTOR AND THEN
TO BUILD IT FROM THERE.
AND THAT'S WHERE YOU
HAVE TO EXPERIMENT.
YOU GOT TO TRY ALL THE
DIFFERENT GEAR TRAINS, TRY
EXPERIMENTING WITH PUTTING ON
THE 75 AND THEN THE 15 AND
ATTACHING IT TO THE OTHERS AND
SEEING WHAT'S HAPPENING TO THE
TORQUE AND EXPERIENCING IT
FOR YOURSELVES HANDS ON.
THAT'S THE BEST
WAY, BEST RESULTS.
NOW, ANOTHER EXPLANATION, VERY
QUICKLY, WHEN WE TALK ABOUT
THE RELATIONSHIP OF RIM
FORCE OF THE GEARS TO THE...
OF THE LEVER ARMS, THE LENGTH,
THE DISTANCE, WHICH WAS THE
TORQUE, THIS IS
ANOTHER EXPLANATION.

The caption changes to “Force versus Torque: The motor is supplying the same amount of torque to each of the gears, it is the length of each gear’s lever arm that determines the amount of force the gear is transmitting.”

She continues THEREFORE, THAT'S
WHAT I WAS MENTIONING.
IF THE LEVER ARM...
IT'S THE SAME TORQUE BEING
GIVEN TO ALL THREE DIFFERENT
GEARS, BUT IF THE LEVER ARM
ON THE GEAR ITSELF IS LONGER,
LIKE THE 75, THEN IT WILL
TRANSMIT LESS FORCE BECAUSE
THINK OF THE REVOLVING DOORS.
IF YOU'RE OFF TO THE LONGER
PART OF THE REVOLVING DOOR,
IT'S MUCH EASIER, SO AS THE
DRIVER GEAR ON THE SHAFT OF
THE MOTOR, THE LARGER THE
WHEEL OR THE LARGER THE GEAR,
IT'S LESS FORCE, AND THEN IT
WILL TRANSMIT TO ITS DRIVEN
GEAR, OKAY?
SO IF YOU START OFF WITH THE
LITTLE ONE AS A DRIVER GEAR,
IT WILL TRANSMIT MORE
FORCE TO THE DRIVEN GEAR.
TRY THAT.
EXPERIMENT WITH IT THIS
WEEK AND IT'D BE KIND OF...
IT'S FUN TO SEE THE RESULTS.
AS I MENTIONED, QUICKLY, I DO
HAVE SOMETHING INTERESTING HERE.
IT IS A...
THE SAME AS THE FELLOW,
MARQUETTE, WAS MENTIONING...
I'M GOING TO PUT THIS IN FRONT
OF YOU A LITTLE BIT CLOSER.
AND WHAT YOU SEE IS AN ACTUAL
TORQUE WRENCH, AND IT'S WHAT
PEOPLE WOULD USE IN A MECHANIC
SHOP, LET'S SAY, OKAY?
AND IF I BRING IT IN A TAD AND
TURN IT AROUND SO THAT YOU CAN
READ IT, BRING IT EVEN CLOSER,
YOU WILL NOTE, IF I MOVE THIS,
IT SAYS IN NEWTON METRES,
OKAY, NEWTON METRES.
SO THEY ACTUALLY USE THIS, AND
IF YOU LOOK AT THE OTHER END,
I'LL GO RIGHT TO THE OTHER
END, THAT'S WHY IT'S CALLED
A TORQUE WRENCH.
IT'S TO MEASURE THE TORQUE
ON NUTS AND BOLTS, OKAY?
SO THIS SECTION WILL GO INTO
THE NUT AND THEN TIGHTEN IT.
NOW, LOOKING AT IT RIGHT
ACROSS, IF I WERE MYSELF TO
PUT THIS IN AND PUT SOME
PRESSURE, IT WOULD HARDLY
MOVE, OKAY?
BUT TO SHOW YOU, IF I...
IT'S EASY TO PRESS OVER HERE,
BUT FOR IT TO ACTUALLY OCCUR
AT THIS END -- REMEMBER, THE
CLOSER HERE, IT'S MUCH MORE
FORCE -- IT WILL ACTUALLY MOVE
THE STICK HERE TO INDICATE HOW
MANY NEWTON METRES
ONE HAS TO ROTATE.
AND WHY DO WE NEED THIS?
WELL, FOR INSTANCE, IF THE
LEAD BOLTS IN AN ENGINE OF A
CAR, IT HOLDS THE ENGINE
TOGETHER AGAINST THE FORCE OF
THE PISTONS, AND IT'S EXTREMELY
IMPORTANT THAT THE TORQUE MUST
BE PRECISE, AND YOU MAY WANT
TO TORQUE A 40 OR MORE, AND
DEPENDING WHEREVER...

She moves a large silver needle and continues
BUT THEY HAVE TO BE VERY, VERY
PRECISE ABOUT THAT BECAUSE
IF THEY DO NOT USE ENOUGH
TORQUE, IT COULD CAUSE DAMAGE,
OBVIOUSLY, AND IF IT...
IF THEY USE TOO MUCH, AS
WAS MENTIONED IN ONE OF THE
VIDEOS, IT WILL ACTUALLY
BREAK THE NUT, OKAY?
SO THAT'S SOMETHING TO KEEP IN
MIND, THE IMPORTANCE OF IT,
AND THE BEST EXPERIENCE FOR
YOU IS, ONCE AGAIN, TRY IT OUT.
SEE FOR YOURSELVES
HOW THE TORQUE WORKS.
IT CAN BE VERY DIFFICULT, BUT
ONCE YOU VISUALIZE IT AND
EXPERIENCE IT YOURSELF, IT
MAKES THAT MUCH EASIER.
FOR YOUR HOMEWORK, WE HAVE AN
EXCITING LESSON ON THURSDAY.
JUST, FOR YOUR SAKE, LIKE ON
THURSDAY, WE'RE GOING TO BE
TALKING ABOUT THE
DESIGN FOR YOUR...
THE EXTERIOR OF YOUR VEHICLE,
AND THEREFORE, IF YOU CAN,
THIS WEEK, REVIEW WHAT WE'VE
BEEN DOING RIGHT FROM THE
BEGINNING, THE DESIGN PROCESS,
SIMPLE GEARS, COMPOUND GEARS,
TRAINS, GEARS AND MOTORS,
SPEED, WHEEL RIM FORCE, WE
TALKED ABOUT RIM FORCE, AND AT
THIS POINT, AS WELL, WE TALKED
ABOUT NOW TORQUE AND LEVER
ARMS AND ALL THIS INFORMATION
I HOPE YOU'VE KEPT INTO YOUR
LOG FOLDER BECAUSE IT'S VERY
IMPORTANT THAT YOU HAVE ALL
ACCESS TO THAT WHEN YOU
FINALLY COME UP WITH
YOUR FINAL PROTOTYPE.
AND, ONCE AGAIN, THERE'S
SOFTWARE CALLED THE ENCYCLOPEDIA
OF SCIENCE AND THE WAY THINGS
WORK, AND IF YOU GO INTO THE
WAY THINGS WORK OR EITHER ONE,
THEY WILL EXPLAIN TO YOU THERE
ARE THREE DIFFERENT LEVELS
OF THE LEVER, OKAY, AND IT'S
VERY EXCITING TO GO IN THERE
AND FIND OUT WHAT THE LEVELS
ARE AND SO ON.
IF WE HAVE TIME ON THURSDAY,
MAYBE I'LL SHOW YOU
THAT, OR IF YOU COULD DO
IT ON YOUR OWN, THAT WOULD BE
GREAT BECAUSE I CERTAINLY HAD
A LOT OF FUN GOING
THROUGH THE SOFTWARE.
ENJOY AND HAVE A NICE COUPLE
OF DAYS, AND WE'LL SEE YOU ON
THURSDAY, AND IF YOU HAVE ANY
QUESTIONS IN THE NEXT FEW
MINUTES, PLEASE FEEL FREE
TO CALL BY PRESSING POUND 9.
BYE-BYE.

Watch: Torque and Lever Arms ST9