Work done and energy transfer 5.2

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

• A rise in temperature of the object occurs

- Kinetic energy is converted to heat

Question 8

Why does air resistance slow down a projectile?

Answer 8

• The object does work against the air resistance

- Kinetic energy is converted into heat, slowing down the object