READ AND FILL BLANKS FOR FULL CREDITS. What is a torque ? (a quantity that measures how efficient your force is to rotate an object)
bank: clockwise torque axis push counterclockwise fulcrum open rotate efficient force lever arm straight
A torque (or turning effect) is what causes an object to rotate. The same way a force is what causes an object to move in a straight line.
Let's say you want ot open the door of the Physics lab by pushing it: (read legends)
The torque T measures how __________is your action in moving the door.
The torque depends on your ______(the force F in drawing) and on the distance L (called lever arm) between the _______ and the point where the force is applied.
The torque T is positive if the door opens ____________. The torque is negative if the door opens ____________. (see legends)
The lever arm is the distance between the _________ and the point where the _________ is applied.
We suppose the force to be perpendicular to the door. If the force applied is along the door (// to the door), the door does not _______.
so the __________ T is 0 (the force F is unefficient in opening the door).
Again, a torque is what causes objects to __________. A force is what causes objects to move in a ________ line.
The axis of rotation of the door or any rotating object is called the _________. The distance betwen the fulcrum and the point where the force is applied
is called the _______ _________.
PURPOSE: READ.
In this lab you will find the mathematical expression for torque. You will derive the relationship between torque T, force F and distance L from the fulcrum.
For the lab you will work with a meter stick that will work like a see saw. You will use masses to apply forces (weights) on the meter stick.
The axis of rotation (fulcrum) will be located in the middle of the meter stick.
You will determine the relationship between masses (weights and distances from the fulcrum (axis of rotation) for a balanced see-saw (balanced meter stick).
DISCUSSION: FILL BLANKS
bank: fulcrum balance question rest equilibrum rorate zero torque torques
An object at________ (not moving) is in _________. The sum of the forces exerted (net force ) is _________. (no acceleration)
The resting object also shows another aspect of equilibrium. Because the object has no rotation, the sum of the _______ exerted is zero. (the quantity that
measure how efficient you are in rotating an object).
The see-saw is a simple machine that rotates about a pivot or _______ (axis). It is a type of lever. Levers make work easier to accomplish a variety of tasks. Suppose you try to balance an elephant on a see saw. The elephant weighs 2000 kg (4000 pounds) and you weighs 50kg (100 pounds).
The elephant is to stand 2m from the _______. How far from the fulcrum you need to stand from the fulcrum, on the other side, to ________ the elephant ?
This lab will try to answer this _________. You are balancing the elephant only if the torque exerted by the elephant = ________ exerted by you.
To solve this problem we need to find the formula for torque. (the quantity that makes objects __________ around a axis (fulcrum)
PROCEDURE:
STEP1: CArefully balance a meter stick horizontally on a wedge or knife-edge. Suspend a 200g mass 10cm from the fulcrum.
Suspend a 100g mass on the other side of the fulcrum at the point that balances the meter stick.
REcord the masses and distances from the fulcrum in TABLE A.
STEP2: MAke more trials to fill in TABLE A. You can do this by using the masses of STEP 1 and changing their positions. For instance, you can move the heavier mass to a new location 5 cm fartheraway, and then rebalance the meterstick with with th lighter mass. You can also change the value of the masses, Replace the heavier mass with another mass and rebalance the lever by moving the lighter mass. Record the masses and distances from the fulcrum in TABLE A. Be sure to take into account the mass of any hanger or clamp.
STEP 3: Try to find a pattern in the data of TABLE A: compare m1 x L1 to m2 x L2. Are these products equal ?
STEP4: fill blanks :
Conclusion: the objects are in equlibrum when mass1 x L1 = mass2 x L2
or WEIGHT1 x LEVER ARM1 = ________ x ________
You just found the expression for the torque. Torque = ______ x distance from ___________.
WHen objects are in equilibrum, all the _________ have to balance each other.
so torque on left side of the axis = _________ on the _______ side of the axis.
ANALYSIS
2) Can a heavier mass be balanced by a lighter one? EXplain how ?
________________________________________________________________________________________________
1) With the help of your partners , use the equation to find the distance a 50kg person should stand from
the fulcrum to balance the elephant/ Show your work.
2) If you are playing see saw- with your younger sister (who weighs much less than you), what can you do to balance the see saw? Mention at least two things.
3) Suppose you weigh 80 lbs and your brother weihs 40lbs. If your brother sits 6ft away from the fulcrum, where your brother should sit to balance you ?
GOING FURTHER. FROM NOW ON:
TORQUE = FORCE (N) exerted to rorate an object x LEVER ARM (m)
or T = F x L units for torque = N.m
A TORQUE IS A QUANTITY THAT MEASURE HOW EFFICIENT YOU ARE IN ROTATING AN OBECT.
1)
You use 2 wrenches to rotate a nut.
The large wrench is 24 cm long and the small one is 12 cm long. You apply a 50N force at the end to rotate the nut.
Compute the torques applied to each of the wrench. Which one will be easier to rotate ? (convert cm to m first)
2)
You try to lift a big rock with a force F . the small rock is your fulcrum or axis of rotation.
l is the lever of arm. (picture) (It is the perpendicular distance from the fulcrum to the
line of action of the force F )
A) If you push at the end of the stick with a force F of 100 N, what is the torque T ? l = 2m
B) if you push twice as close to the fulcrum, what is the torque ? What does it mean?
C) this system is called a ____________ , this machine magnifies your force.
D) if you multiply the lever arm by 2 (l is multiplied by 2), the torque is multiplied by __________
so it is __________ to lift the rock. A torque measures how ________ you are in rorating the load (the rock)./
3)
If you want to reach equilibrium the torque on the right of the fulcrum has to __________ the torque on the left.
(the net torque is then zero)
A) Find the torque applied by the 5N weight. Tr = _________ (convert the 20 cm into m)
B) solve for the distance l between the 3N weight and the fulcrum so equilibrium is reached.
(hint : Torque on the left = torque on the righ for equilibrum to be reached)
4)
If F1 = 10N and l1 = 30 cm
Find F2 if l2 = 25 cm
hints: F1 x l1 = F2 x l2 solve for F2
5)
A) If F2 = 10 N and l2 = 20 cm
Find F1 if l1 is twice l2.
hints: F2 x l2 = F1 x l1 substitute l1 by 2 x l2 , solve for F1
SO IF YOU MULTIPLY YOUR DISTANCE BY 2, THE TORQUE IS MULTIPLY BY 2
based on that observation answer this question
B) if you want to play seesaw with your sister, 3 times lighter than you,
where would you sit relative to the fulcrum? Your sister is sitting at 3m from the fulcrum ?
hints: take an example. you = 90 kg (F1). sister = 30 kg (F2) and l2 = 3m solve for l1
6) A motorcycle head bolt is torqued to 25.0 Nm . What length shaft do we need on a wrench
to exert a maximum force of 70.0 N?
hint: torque = force x distance, solve for distance.
7) An automobile bolt is torqued to 27.0 Nm. If the length of the wrench is 30.0 cm what force
is applied to the wrench ? (convert cm to me before computing the force)
8) if 13 Nm of torque is applied to a bold with an applied force of 28 N, what is the length of the wrench ?
9) 2 persons sit on a seesaw. Jack sits 2.05 m from the fulcrum and has a mass of 60kg.
Gill sits at 3.0 from the fulcrum. The system is in equilibrium. WHat is the mass of Gill ?
hints: torque 1 = torque 2 so W1 x L1 = W2 x L2 or m1 x L1 = m2 x L2, solve for m2
10) optional only . For Physics lovers
A uniform meter rule of mass 100g balances at the 40cm mark when a mass X is placed
at the 10cm mark. What is the value of X?
hints: the fulcrum is at the 40cm marks, the weight of the ruler is at the 50cm mark
and weight of X is at the 10cm mark. draw a diagram.
bank: clockwise torque axis push counterclockwise fulcrum open rotate efficient force lever arm straight
A torque (or turning effect) is what causes an object to rotate. The same way a force is what causes an object to move in a straight line.
Let's say you want ot open the door of the Physics lab by pushing it: (read legends)
The torque T measures how __________is your action in moving the door.
The torque depends on your ______(the force F in drawing) and on the distance L (called lever arm) between the _______ and the point where the force is applied.
The torque T is positive if the door opens ____________. The torque is negative if the door opens ____________. (see legends)
The lever arm is the distance between the _________ and the point where the _________ is applied.
We suppose the force to be perpendicular to the door. If the force applied is along the door (// to the door), the door does not _______.
so the __________ T is 0 (the force F is unefficient in opening the door).
Again, a torque is what causes objects to __________. A force is what causes objects to move in a ________ line.
The axis of rotation of the door or any rotating object is called the _________. The distance betwen the fulcrum and the point where the force is applied
is called the _______ _________.
PURPOSE: READ.
In this lab you will find the mathematical expression for torque. You will derive the relationship between torque T, force F and distance L from the fulcrum.
For the lab you will work with a meter stick that will work like a see saw. You will use masses to apply forces (weights) on the meter stick.
The axis of rotation (fulcrum) will be located in the middle of the meter stick.
You will determine the relationship between masses (weights and distances from the fulcrum (axis of rotation) for a balanced see-saw (balanced meter stick).
DISCUSSION: FILL BLANKS
bank: fulcrum balance question rest equilibrum rorate zero torque torques
An object at________ (not moving) is in _________. The sum of the forces exerted (net force ) is _________. (no acceleration)
The resting object also shows another aspect of equilibrium. Because the object has no rotation, the sum of the _______ exerted is zero. (the quantity that
measure how efficient you are in rotating an object).
The see-saw is a simple machine that rotates about a pivot or _______ (axis). It is a type of lever. Levers make work easier to accomplish a variety of tasks. Suppose you try to balance an elephant on a see saw. The elephant weighs 2000 kg (4000 pounds) and you weighs 50kg (100 pounds).
The elephant is to stand 2m from the _______. How far from the fulcrum you need to stand from the fulcrum, on the other side, to ________ the elephant ?
This lab will try to answer this _________. You are balancing the elephant only if the torque exerted by the elephant = ________ exerted by you.
To solve this problem we need to find the formula for torque. (the quantity that makes objects __________ around a axis (fulcrum)
PROCEDURE:
STEP1: CArefully balance a meter stick horizontally on a wedge or knife-edge. Suspend a 200g mass 10cm from the fulcrum.
Suspend a 100g mass on the other side of the fulcrum at the point that balances the meter stick.
REcord the masses and distances from the fulcrum in TABLE A.
STEP2: MAke more trials to fill in TABLE A. You can do this by using the masses of STEP 1 and changing their positions. For instance, you can move the heavier mass to a new location 5 cm fartheraway, and then rebalance the meterstick with with th lighter mass. You can also change the value of the masses, Replace the heavier mass with another mass and rebalance the lever by moving the lighter mass. Record the masses and distances from the fulcrum in TABLE A. Be sure to take into account the mass of any hanger or clamp.
| TRIAL | 1 | 2 | 3 | 4 | 5 | 6 |
| m1 = MASS 1 (g) (force F) |
100 | |||||
| l1 = DISTANCE FROM FULCRUM (cm) (lever arm L) |
||||||
| multiply m1 x L1 | ||||||
| m2 = MASS 2 (g) | 200 | |||||
| l2 = DISTANCE FROM FULCRUM (cm) | ||||||
| multiply m2 x L2 |
STEP 3: Try to find a pattern in the data of TABLE A: compare m1 x L1 to m2 x L2. Are these products equal ?
STEP4: fill blanks :
Conclusion: the objects are in equlibrum when mass1 x L1 = mass2 x L2
or WEIGHT1 x LEVER ARM1 = ________ x ________
You just found the expression for the torque. Torque = ______ x distance from ___________.
WHen objects are in equilibrum, all the _________ have to balance each other.
so torque on left side of the axis = _________ on the _______ side of the axis.
ANALYSIS
2) Can a heavier mass be balanced by a lighter one? EXplain how ?
________________________________________________________________________________________________
1) With the help of your partners , use the equation to find the distance a 50kg person should stand from
the fulcrum to balance the elephant/ Show your work.
2) If you are playing see saw- with your younger sister (who weighs much less than you), what can you do to balance the see saw? Mention at least two things.
3) Suppose you weigh 80 lbs and your brother weihs 40lbs. If your brother sits 6ft away from the fulcrum, where your brother should sit to balance you ?
GOING FURTHER. FROM NOW ON:
TORQUE = FORCE (N) exerted to rorate an object x LEVER ARM (m)
or T = F x L units for torque = N.m
A TORQUE IS A QUANTITY THAT MEASURE HOW EFFICIENT YOU ARE IN ROTATING AN OBECT.
1)
You use 2 wrenches to rotate a nut.
The large wrench is 24 cm long and the small one is 12 cm long. You apply a 50N force at the end to rotate the nut.
Compute the torques applied to each of the wrench. Which one will be easier to rotate ? (convert cm to m first)
2)
You try to lift a big rock with a force F . the small rock is your fulcrum or axis of rotation.
l is the lever of arm. (picture) (It is the perpendicular distance from the fulcrum to the
line of action of the force F )
A) If you push at the end of the stick with a force F of 100 N, what is the torque T ? l = 2m
B) if you push twice as close to the fulcrum, what is the torque ? What does it mean?
C) this system is called a ____________ , this machine magnifies your force.
D) if you multiply the lever arm by 2 (l is multiplied by 2), the torque is multiplied by __________
so it is __________ to lift the rock. A torque measures how ________ you are in rorating the load (the rock)./
3)
If you want to reach equilibrium the torque on the right of the fulcrum has to __________ the torque on the left.
(the net torque is then zero)
A) Find the torque applied by the 5N weight. Tr = _________ (convert the 20 cm into m)
B) solve for the distance l between the 3N weight and the fulcrum so equilibrium is reached.
(hint : Torque on the left = torque on the righ for equilibrum to be reached)
4)
If F1 = 10N and l1 = 30 cm
Find F2 if l2 = 25 cm
hints: F1 x l1 = F2 x l2 solve for F2
5)
A) If F2 = 10 N and l2 = 20 cm
Find F1 if l1 is twice l2.
hints: F2 x l2 = F1 x l1 substitute l1 by 2 x l2 , solve for F1
SO IF YOU MULTIPLY YOUR DISTANCE BY 2, THE TORQUE IS MULTIPLY BY 2
based on that observation answer this question
B) if you want to play seesaw with your sister, 3 times lighter than you,
where would you sit relative to the fulcrum? Your sister is sitting at 3m from the fulcrum ?
hints: take an example. you = 90 kg (F1). sister = 30 kg (F2) and l2 = 3m solve for l1
6) A motorcycle head bolt is torqued to 25.0 Nm . What length shaft do we need on a wrench
to exert a maximum force of 70.0 N?
hint: torque = force x distance, solve for distance.
7) An automobile bolt is torqued to 27.0 Nm. If the length of the wrench is 30.0 cm what force
is applied to the wrench ? (convert cm to me before computing the force)
8) if 13 Nm of torque is applied to a bold with an applied force of 28 N, what is the length of the wrench ?
9) 2 persons sit on a seesaw. Jack sits 2.05 m from the fulcrum and has a mass of 60kg.
Gill sits at 3.0 from the fulcrum. The system is in equilibrium. WHat is the mass of Gill ?
hints: torque 1 = torque 2 so W1 x L1 = W2 x L2 or m1 x L1 = m2 x L2, solve for m2
10) optional only . For Physics lovers
A uniform meter rule of mass 100g balances at the 40cm mark when a mass X is placed
at the 10cm mark. What is the value of X?
hints: the fulcrum is at the 40cm marks, the weight of the ruler is at the 50cm mark
and weight of X is at the 10cm mark. draw a diagram.
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