P5 - Work done and energy transfers

Question 1

What does it mean if a force is said to do

‘work’?

Answer 1

The force causes an object to be

displaced through a distance.

Question 2

What is the equation used to calculate

work done? Give appropriate units.

Answer 2

Work done = Force x Distance
Work done (Joules), Force (Newtons), 
Distance (metres)

Question 3

What distance must be used when

calculating work done?

Answer 3

It must be the distance that is moved

along the line of action of the force.

Question 4

Under what circumstance is 1 joule of

work done?

Answer 4

When a force of 1 Newton causes a

displacement of 1 metre.

Question 5

How many Newton-metres are equal to 1

joule of energy?

Answer 5

1 Nm = 1 J

Question 6

How much work is done by the force
acting on the below object over a
distance of 5m?

Answer 6

10 x 5 = 50 Nm

= 50 J

Question 7

What occurs when work is done against

frictional forces?

Answer 7

What occurs when work is done against

frictional forces?

Question 8

Why does air resistance slow down a

projectile?

Answer 8

● The object does work against the air
resistance
● Kinetic energy is converted in to heat,
slowing down the object