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 * 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 allong the line of action of the force

Question 4

Under what circumstance is 1 joule 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

1Nm = 1J

Question 6

How much work is done by the force acting on the below object over a distance of 5m?
____________
————– [ ]
10N —————–

Answer 6

10 * 5 = 50Nm
= 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 done a projectile?

Answer 8

• The object does work against the air resistance
• Kinetic energy is convertedin to heat, slowing down the object