Work done and energy transfer (5.2) (M)

Question 1

When is work done on an object?

Answer 1

Work is done on an object when a force causes an object to move through a distance (W = Fs)

Question 2

When does force do work on the object?

Answer 2

when the force causes a displacement of the object

Question 3

When is one joule of work done?

Answer 3

when a force of one newton causes a displacement of one metre

Question 4

How many newton-metres is 1 joule equal to?

Answer 4

1 joule = 1 newton-metre

Question 5

Work is done when a car breaks along a road, describe the energy transfer

Answer 5

Transfer of kinetic energy store in cars to thermal energy store of brakes and surroundings due to work done by forces

need to know work done by forces transfers for this topic

Question 6

Work done against the frictional forces acting on an object causes a (…) in the temperature of the object.

Answer 6

rise

Question 7

3 marks

A cyclist has a maximum speed, how does cycling uphill affect the maximum speed of this cyclist?

Answer 7

The maximum speed will decrease

Maximum power is constant

So more work needs to be done against gravity

Question 8

4 marks

Describe the energy transfer from the ball to earth when the ball hits the ground?

Answer 8

velocity just after bounce is less than just before bounce

so the ball has lost energy

(loss of) ke or (reduced) gpe

total energy of ball and Earth / ground is constant