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A secondary school revision resource for AQA GCSE Additional Science about force, kinetic energy and momentum

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6) Momentum: a property of moving objects

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6) Momentum: a property of moving objects

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1) Start with number 1, write down the definition and draw an image which will help you to remember the definition.

2) Click on the website link and make a mind map of key information, putting things into your own words and adding diagrams.

3) Repeat this for topic 2-6.

4) Answer the exam questions and self-assess using the mark schemes.

5) Reflect on which topics you still need more help on and visit these in the textbook/speak to your teacher.

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BBC - GCSE Bitesize: Power - work and time

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A secondary school revision resource for Edexcel Additional GCSE Science about forces for transport and work and power

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BBC - GCSE Bitesize: Gravitational potential energy (GPE)

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A secondary school revision resource for OCR Gateway GCSE Additional Science about forces for transport and the energy of games and theme rides

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A secondary school revision resource for AQA GCSE Additional Science about force, kinetic energy and momentum

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Work done and energy transferred are measured in joules (J). The work done on an object can be calculated if the force and distance moved are known.

A change in momentum happens when a force is applied to an object that is moving or is able to move. The total momentum in an explosion or collision stays the same.

You should know, and be able to use, the relationship between work done, force applied and distance moved.

Background

Work and energy are measured in the same unit, the joule (J). When an object is moved by a force, energy is transferred and work is done. But work is not a form of energy - it is one of the ways in which energy can be transferred.

The equation

This equation shows the relationship between work done, force applied and distance moved:
work done (joule, J) = force (newton, N) × distance (metre, m)
The distance involved is the distance moved in the direction of the applied force.

Check your understanding of this by having a go at the activity.

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Work done and energy transferred are measured in joules (J). The work done on an object can be calculated if the force and distance moved are known. A change in momentum happens when a force is applied to an object that is moving or is able to move.

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5) Kinetic energy: energy of an object dependent on its mass and its speed.

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5) Kinetic energy: energy of an object dependent on its mass and its speed.

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1) Resultant force: a single force that represents all of the combined forces acting on an object.

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1) Resultant force: a single force that represents all of the combined forces acting on an object.

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3) Gravitational potential energy: the energy that an object has because it is surrounded by a gravitational field.

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3) Gravitational potential energy: the energy that an object has because it is surrounded by a gravitational field.

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2) Power: the work done or energy transferred in a given time.

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2) Power: the work done or energy transferred in a given time.

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4) Work done: When a force causes an object to move a certain distance.

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4) Work done: When a force causes an object to move a certain distance.

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A stationary object remains stationary if the sum of the forces acting upon it - resultant force - is zero. A moving object with a zero resultant force keeps moving at the same speed and in the same direction.

If the resultant force acting on an object is not zero, a stationary object begins to accelerate in the same direction as the force. A moving object speeds up, slows down or changes direction.

Acceleration depends on the force applied to an object and the object's mass.

You should be able to use the idea of the resultant force on an object to determine its movement.

The resultant force

An object may have several different forces acting on it, which can have different strengths and directions. But they can be added together to give the resultant force. This is a single force that has the same effect on the object as all the individual forces acting together.

When all the forces are balanced, the resultant force is zero. In this case:

a stationary object remains stationary

a moving object keeps on moving at the same speed in the same direction

For example, in the diagram of the weightlifter, the resultant force on the bar is zero, so the bar does not move. Its weight acting downwards is balanced by the upward force provided by the weightlifter.

The longer the arrow, the bigger the force. In this diagram, the arrows are the same length, so we know they are the same size.

When all the forces are not balanced, the resultant force is not zero. In this case:

A stationary object begins to move in the direction of the resultant force.

A moving object speeds up, slows down or changes direction depending on the direction of the resultant force.

In this diagram of the weightlifter, the resultant force on the bar is not zero. The upwards force is bigger than the downwards force. The resultant force acts in the upwards direction, so the bar moves upwards.

In this next diagram of the weightlifter, the resultant force on the bar is also not zero. This time, the upwards force is smaller than the downwards force. The resultant force acts in the downwards direction, so the bar moves downwards.

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A stationary object remains stationary if the sum of the forces acting upon it - resultant force - is zero. A moving object with a zero resultant force keeps moving at the same speed and in the same direction.