Tasks: Thursday, April 20, 2023

1) Finish Wednesday’s worksheet

2) Activity 9A

3) H/W Set 5

separating blood/plasma oil cleaning pilot trainingwatch Jeremy Clarkson (4 min)

Application: centrifuges

Torque• Torque is the turning

effect of a “force couple” acting around the centre of mass

• Symbol: • Measured in Nm• Vector: acts clockwise

or anticlockwise• Force and distance from

pivot must be perpendicular

r

F

Fr►Does this cause pure rotation?

NONO

axle reaction force means no net translational motion

pure rotation results

Example:The diagram shows the rear gear wheels on a mountain bike.The rider pushes with a force of 200N when the chain is on the largest gear wheel, which has radius 7.0cm

a) Calculate the torque the chain applies to the rear wheel

b) Calculate the force needed to apply the same torque when the rider changes gear and the chain is shifted to the smallest gear wheel, which has radius 3.0cm