Torque & Equilibrium

Demo - Balancing Act

Torque “Turning effect about a pivot produced by a perpendicular force” τ = torque (also called ‘moment’) F = force d = distance between the pivot and the point where the force is applied Torque is measured in ______

“We want more torque!”

Whenever you calculate a torque, state which way it is. Question: “Does torque have direction?” YES – a torque is either “clockwise” or “anticlockwise” Whenever you calculate a torque, state which way it is.

Anticlockwise Torque vs. Clockwise Torque

Example #1 12 kg 7 kg 40 cm 60 cm Calculate the anticlockwise torque Calculate the clockwise torque Which is greater? Anticlockwise torque or clockwise torque?

Example #2 7 kg 65 cm 35 cm Calculate the anticlockwise torque Calculate the clockwise torque Which is greater? Anticlockwise torque or clockwise torque?

Example #3 9 kg 4 kg 4 kg 40 cm 30 cm 30 cm Calculate the total anticlockwise moment Calculate the total clockwise moment Is the seesaw balanced?

To balance the seesaw, where does Bob have to be? Aaron (80 kg) Bob (20 kg) Aaron is 1.5 m away from the pivot and Bob is 3 m away from the pivot. Is the seesaw balanced? To balance the seesaw, where does Bob have to be?

Try this: On a very long seesaw, there are one hundred elephants on one end and there is Joshua sitting on the other end. Is this seesaw balanced?

"Give me a place to stand and I will move the earth!" Archimedes

Snoopy and Woodstock are are sitting on a seesaw. Snoopy weighs 12 kg and is sitting 1 m away from the pivot. Woodstock weighs 100 g and is sitting 120 m away from the pivot. Is the seesaw balanced?

The mass of the rock is 1100 kg and it is sitting on one end of the stick, 50 cm away from the pivot as shown in the diagram. If the man exerts a downward force of 70 N to the other end of the stick which is 8 m away from the pivot, would he be able to lift the rock?

Torque can be increased by: Increasing the force Increasing the distance between the pivot and the point where the force is applied

Worksheet – Torque and Moments Questions 1, 2, 3, 4 only