# Work, Energy and Momentum

Some information taken from CGP Physics Revision Guide and Workbook.

Hope it helps x

## Slides in this set

### Slide 1

Work, Energy and

Momentum

Forces in Motion Topic 3…read more

### Slide 2

Work and Energy

· When you transfer energy you do work. We can measure the amount

of work done because:

Work Done = Force x Distance Travelled in the Direction of the Force

Joules = Newtons x Metres

e.g. Two farmers drag an old tractor tyre 5m over flat ground.

They pull with a total force of 340N.

What is the work done?

W = F x D 340 x 5 = 1700J.

W

FxD…read more

### Slide 3

Kinetic Energy

· Kinetic energy is energy of movement.

· It depends on its mass and speed.

Kinetic Energy = ½ x Mass x Velocity²

Joules = ½ x kg x m/s²

e.g. A 100kg bicycle moves at 8 m/s². Important to

Calculate its kinetic energy. square the

velocity first

½ x 100 x (8²) = 3200J/3.2kJ. K.E.

½ x M x V…read more

### Slide 4

Potential Energy

· Energy can be stored as potential energy.

Elastic Potential Energy

· Energy stored when work is done on an elastic object to change its shape.

· Released as kinetic energy (and some heat) when the object springs back

into shape.

Gravitational Potential Energy

· Energy stored in an object when it is risen against gravity.

· You have to move something to increase its gravitational potential energy

and that energy is only released when the object falls.

Gravitational Potential Energy = Weight x Height

Joules = Newtons x Metres

G.P.E.

Weight = Mass x Gravity

WxH…read more

### Slide 5

Power

· If one person does the same amount of work as another, but does it

more quickly, they are said to be more powerful.

Power = work done = energy transferred

time taken time taken

e.g. George pushes a shopping trolley with a force of 100N for 20m in

10 seconds.

Find the power.

Work done = 100 x 20 = 2000

E

Power = 2000 ÷ 10 = 200 Joules

PxT…read more

### Slide 6

Momentum

Momentum

Momentum = Mass x Velocity

kg.m/s = kg x m/s Mass x Velocity

· Momentum is conserved momentum before = momentum after

e.g. Two skaters approach each other, collide and move off together.

At what velocity do they move after the collision?

1. Explain which direction they move to to the right

2. Total momentum before collision = momentum of A + B

= (80 x 2) + (60 x -1.5) = 70 kg.m/s²

3. Total momentum after collision = momentum of A + B

= 140kg x V

Velocity (V) = ?

4. So 140 x V = 70kg V = 0.5 m/s to the right

1.5 m/s

2 m/s

80kg 60kg

(80+60) kg

A B

Before After…read more

### Slide 7

## Related discussions on The Student Room

- I don't buy perpendicular force = no work »
- Momentum/Energy »
- Help me with physics problem (momentum, force, work , and ... »
- Conservation of momentum & energy »
- Help! Physics problem about work,momentum,impulse,and ... »
- Stuck on mechanics problem regarding momentum/work »
- A2: Momentum Q help please :) »
- A-level physics multiple choice question »
- Momentum question »
- Edexcel P2 - 12/06/2014 - 'Unofficial Markscheme' »

## Similar Physics resources:

# Work, Energy and Momentum

Some information taken from CGP Physics Revision Guide and Workbook.

Hope it helps x

- Created by: Cristina
- Created on: 24-12-10 11:09

## Slides in this set

### Slide 1

Work, Energy and

Momentum

Forces in Motion Topic 3…read more

### Slide 2

Work and Energy

· When you transfer energy you do work. We can measure the amount

of work done because:

Work Done = Force x Distance Travelled in the Direction of the Force

Joules = Newtons x Metres

e.g. Two farmers drag an old tractor tyre 5m over flat ground.

They pull with a total force of 340N.

What is the work done?

W = F x D 340 x 5 = 1700J.

W

FxD…read more

### Slide 3

Kinetic Energy

· Kinetic energy is energy of movement.

· It depends on its mass and speed.

Kinetic Energy = ½ x Mass x Velocity²

Joules = ½ x kg x m/s²

e.g. A 100kg bicycle moves at 8 m/s². Important to

Calculate its kinetic energy. square the

velocity first

½ x 100 x (8²) = 3200J/3.2kJ. K.E.

½ x M x V…read more

### Slide 4

Potential Energy

· Energy can be stored as potential energy.

Elastic Potential Energy

· Energy stored when work is done on an elastic object to change its shape.

· Released as kinetic energy (and some heat) when the object springs back

into shape.

Gravitational Potential Energy

· Energy stored in an object when it is risen against gravity.

· You have to move something to increase its gravitational potential energy

and that energy is only released when the object falls.

Gravitational Potential Energy = Weight x Height

Joules = Newtons x Metres

G.P.E.

Weight = Mass x Gravity

WxH…read more

### Slide 5

Power

· If one person does the same amount of work as another, but does it

more quickly, they are said to be more powerful.

Power = work done = energy transferred

time taken time taken

e.g. George pushes a shopping trolley with a force of 100N for 20m in

10 seconds.

Find the power.

Work done = 100 x 20 = 2000

E

Power = 2000 ÷ 10 = 200 Joules

PxT…read more

### Slide 6

Momentum

Momentum

Momentum = Mass x Velocity

kg.m/s = kg x m/s Mass x Velocity

· Momentum is conserved momentum before = momentum after

e.g. Two skaters approach each other, collide and move off together.

At what velocity do they move after the collision?

1. Explain which direction they move to to the right

2. Total momentum before collision = momentum of A + B

= (80 x 2) + (60 x -1.5) = 70 kg.m/s²

3. Total momentum after collision = momentum of A + B

= 140kg x V

Velocity (V) = ?

4. So 140 x V = 70kg V = 0.5 m/s to the right

1.5 m/s

2 m/s

80kg 60kg

(80+60) kg

A B

Before After…read more

### Slide 7

## Comments

No comments have yet been made

## Similar Physics resources:

## Related discussions on The Student Room

- I don't buy perpendicular force = no work »
- Momentum/Energy »
- Help me with physics problem (momentum, force, work , and ... »
- Conservation of momentum & energy »
- Help! Physics problem about work,momentum,impulse,and ... »
- Stuck on mechanics problem regarding momentum/work »
- A2: Momentum Q help please :) »
- A-level physics multiple choice question »
- Momentum question »
- Edexcel P2 - 12/06/2014 - 'Unofficial Markscheme' »

## Comments

No comments have yet been made