Page 132 - Knowledge Organiser Yr7 24-25

2. Work Done
2.1
What is work done?
A measure of how much energy is transferred from one store to another.
2.2
When is work done?
When a force moves an object over a distance against a resistive force (e.g. gravity or friction).
2.3
Why is lifting a box off the ground an example of work done?
A force is used to move the box a vertical distance against the force of gravity.
2.4
Why is sliding a heavy book across the table an example of work done?
A force is used to move the book a horizontal distance against the force of friction.
4. Stretching and Squashing
4.1
What is deformation?
When a force causes an object to
change shape.
4.2
Name two ways objects can
be deformed.
Objects can be stretched or squashed.
4.3
What causes compression?
Squashing an object.
Joules (J).
A force of 1N causes a movement of 1m. Work done = force x distance (W= F d). 1000m.
100cm.
4.4 What causes tension?
Stretching an object.
2.5 What is the unit for work done?
2.6 If 1J of work is done, what does this mean?
2.7 What is the equation to calculate work done?
2.8 How many metres are in 1km?
2.9 How many cm are in 1m?
3. Balanced and Unbalanced Forces
3.1 What is meant by a balanced pair of forces?
3.2 What does stationary mean?
3.3 If an object is stationary, are the forces acting on the object balanced or unbalanced?
3.5 If the forces on an object are unbalanced, what will happen to the object?
3.6 What is a resultant force?
When forces acting on an object are the same size but in opposite directions. An object that is not moving.
Balanced (they are in equilibrium).
It will accelerate (get faster and faster) or decelerate (get slower and slower).
The overall force acting on an object which has the same effect as all the forces combined.
3.4
If an object is travelling at constant speed, are the forces acting on the object balanced or unbalanced?
Balanced (they are in equilibrium).
3.7
If more than one force is acting on an object in the same direction, how do you find the resultant force?
By adding the forces together.
3.8
If there are forces acting on an object in opposite directions, how do you find the resultant force?
By finding the difference between the size of the forces.
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Knowledge Base: Science 7.6 Forces Year 7