Torque

Definition

The tendency of a force applied to an

object to cause rotation about an axis.

F

rFactors affecting the Torque

F

r

Torque is a product of the moment arm (r) and

the force F

= r F sin

F

r

F

r

F

sin90 = 1

Moment of Inertia

A property of an object that depends on the distribution of mass about the axis of rotation.

Mass close to the axis of rotation = smaller moment of inertia

Mass at a distance from the axis of rotation = larger moment of inertia

I

r = 1.5 mF = 100 N= 32o

= 10 kgm2 = ?

θ

r = 0.25

F = 100 N

I = 20 kgm2

What is v at the edge of the wheel after 2 seconds?

vi = 0

R = 0.75m

sin 0.25 100 sin90 25rF Nm

225

1.2520

radsI

1.25 2 2.5f iradt s

0.75 2.5 1.875mv r s

Note, foot speed is only

0.25 2.5 0.625mv r s