Work

Question 1

Write down the equation used to calculate work done.

Answer 1

Work done = force x distance

Question 2

What unit is work measured in?

Answer 2

Joules (J)

Question 3

True or False: Work done and energy transferred are the same thing.

Answer 3

True.

Question 4

Jane lifts a book onto a high shelf. Which energy store of the book has increased?

Answer 4

Gravitational.

Question 5

Jane lifts a book from the floor onto a high shelf. The book now has 30J of energy in the gravitational sore. How much work has Jane done?

Answer 5

30J

Question 6

Stephen moves a block a distance of 0.2m using a force of 4N. How much work has been done?

Answer 6

4 x 0.2 = 0.8J

Question 7

Sally uses a force of 2N to lift an object 1.5m. How much work is done?

Answer 7

2 x 1.5 = 3J

Question 8

Give two ways to increase the amount of work done.

Answer 8

Increase the force applied, increase the distance moved.

Question 9

If you use a 40N force to lift a bag and do 20J of work, how far do you lift it?

Answer 9

20/40= 0.5m

Question 10

Calculate the work done by a car engine using a force of 500N to move a car 200m.

Answer 10

100,000N

Question 11

How much work is done by a shopkeeper who uses a force of 50N to lift a box 1.5m.

Answer 11

50 x 1.5 = 75J

Question 12

How much work is done if a force of 12N moves an object a distance of 5m?

Answer 12

12 x 5 = 60J

Question 13

Draw a labelled diagram to show how you can use a lever to lift up a heavy box.

Answer 13

Idea that a lever is used with a small input force over a large distance so the large output force moves a small distance.

Question 14

A pulley system can make it easier to lift a load. The force you use is smaller but the distance your hand moves is _______.

Answer 14

Larger

Question 15

A car with 1500J of energy in its kinetic store is brought to a stop in 3m. How much force did the brakes apply?

Answer 15

1500/3= 500N

Question 16

Name two types of simple machine.

Answer 16

Pulleys, levers.

Question 17

Two pulleys are used to lift a weight of 20N through a distance of 5m. How far does the input force have to move?

Answer 17

2 x 5 = 10m

Question 18

Three pulleys are used to lift a weight of 45N through a distance of 3m. How much input force is needed?

Answer 18

45/3 = 15N

Question 19

Explain how using a screwdriver to open a paint tin is useful.

Answer 19

The small input force moves a large distance and so the large output force moves a small distance. This is a force multiplier.

Question 20

Explain how a human arm is a distance multiplier.

Answer 20

A large inpiut force moves a small distance, so the small output force can move a large distance.