GCSE OCR A – Knowledge Test

P4 – Explaining Motion

Name……………………………………….. Date…………………

P4.1 How can we describe motion?

1. A car takes 120 s to travel 2.4 km.

What is its speed?

= ........................................ m / s [1]

2. Explain what is meant by the following terms.

(i) instantaneous speed

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(ii) average speed

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3. Write down the definition of displacement

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4. (i) On the axes below, sketch a distance-time (or displacement-time) graph for an object that is:

A. stationary B. moving at constant speed C. moving with increasing speedD. moving with decreasing speed

[4]

5. Look at the distance-time graph below.

At which point is the object going the fastest?

......................................................................................................................................................... [1]

6. The graph shows a rocket taking off.

How fast is the rocket moving upwards?

= ........................................ m / s [1]

7. On the axes below, sketch a speed-time graph for an object that is:

A. stationary B. moving in a straight line with constant speed C. moving in a straight line with steadily increasing speed D. moving in a straight line with steadily decreasing speed

[4]8. Write down the definition of acceleration

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9. Explain what is meant by the following terms.

(i) instantaneous velocity

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10. This is the velocity time graph for a car.

On the same axes above, sketch a velocity-time graph for the same car moving in the opposite direction with the same speed.

[1]

11. The graph below is a distance-time graph for a person walking.

On the axes below, sketch a velocity-time graph for sections C and D. You do not need to include any numbers.

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12. Here is the velocity-time graph for a ball during its fall.

Calculate the acceleration of the ball during its fall.

= ........................................ m / s2 [1]

13. If a car increases in velocity from +5 m/s to +15 m/s in three seconds, what is its acceleration?

= ........................................ m / s2 [1]

P4.2 What are forces?

1. Complete the below sentence.

A force arises from an .................................... between two objects. [1]

2. When two objects interact, both always experience a force.

What is the name given to these pair of forces?

......................................................................................................................................................... [1]

3. The diagram shows the force of a book acting on a table.

Add an arrow to show the force of the table acting on the book. [1]

4. When a football player kicks a ball there is a force on the ball. This force is part of an interaction pair.

Describe the partner force of the kicking force in the interaction pair.

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5. A child pushes a toy across the floor.

Describe the force between the toy and the floor as the child pushes it.

You should include

the name of the force between the toy and the floor the direction this force acts compared to the direction the toy moves.

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6. A child goes for a walk on the footpath and then stands still.

The child’s feet push down on the ground with a force. This force is part of an interaction pair.

Describe the force between the child and the ground when it is stationary.

You should include

the name of the force between the child and the ground the direction this force acts compared to force created from the child.

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7. A lorry is travelling along a road.

Add labels to the diagram below to show the forces acting on the lorry.

Choose from the following friction reaction weight

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8. Explain why it is easier to walk or drive across grass than it is to walk or drive on ice.

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9. Use the idea of a pair of equal and opposite forces to explain how rockets produce a driving force.

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P4.3 What is the connection between forces and motion?

1. The diagram has four labeled arrows showing four forces acting on the car.

(i) Write down the pair of forces which are equal in size when the car is stationary

............................... and .........................[1]

2. Calculate the resultant force on the below diagram and give the direction.

......................................................................................................................................................... [1]

3. Complete the below sentence.

If a resultant force acts on an object, it causes a change of ...................................... in the

......................................of the force. [1]

4. An object has a mass of 60 kg and a velocity of 2 m/s.

Calculate the objects momentum and give the correct units.

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5. An object with a mass 1000 kg slowed down from 30 m/s to 15 m/s in 20 seconds.

(i) What was the objects change in momentum.

Give the unit.

change in momentum = ................... unit ................ [1]

(ii) What was the force acting on the object when it slowed?

force = ................... unit ................ [2]

6. The following question is about a person who is riding a bike.

Complete the below sentences.

The person riding the bike provides the ............................................ force for the bike.

Air resistance supplies a ............................................ force. [2]

7. The motion of an object depends on the size of each force.

Draw three straight lines to show what happens to the speed of the motorbike as the forces change.

speed of the object forces

changes from 15 m/s to 20 m/s the driving force is the same as the counter force

changes from 15 m/s to 10 m/s the driving force is greater than the counter force

stays constant at 15 m/s the driving force is less than the counter force

[1]

8. Complete the below sentence.

In situations involving a change in momentum (such as a collision), the ........................................the

duration of the impact, the ........................................the average force for a given change in

momentum. [1]

9. Explain how seatbelts, crumple zones, air bags, and cycle and motorcycle helmets reduce the injury in a collision.

the duration of the impact the change in momentum involved the force involved

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10. There are two vertical forces acting on a ball as it falls.

(i) Label these two forces. [1]

11. If the resultant force on an object is zero, its momentum does not change.

Explain what happens to the objet if it is;

stationary

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already moving

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P4.4 How can we describe motion in terms of energy changes?

1. Explain what is meant by the term kinetic energy

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2. What happens to the amount of gravitational potential energy an object has as it is raised?

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3. State the term that describes what happens when a force moves an object

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4. A child pulls an object across the floor at a steady speed.

The child uses a force of 10.0 N to move the object 2 metres.

Calculate the work done on the object.

work done = ................... J [2]

5. Complete the below sentence.

When ..................................... is done on an object, ..................................... is transferred to the

object and when ..................................... is done by an object,..................................... is

transferred from the object to something else. [2]

6. When an object is lifted to a higher position above the ground, work is done by the lifting force.

What type of energy has increased in the object?

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7. An object is lifted 4.5 m above the ground. It gains 6750 J of energy.

What is the weight of the object?

weight = ................... N [2]

8. When a force acting on an object makes its velocity increases.

What type of energy has increased in the object?

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the force does work on the object and this results in an increase in its

9. Complete the below sentence.

The greater the mass of an object and the faster it is moving, the ............................................its

kinetic energy. [1]

10. An object has a mass of 250 kg. The speed of the object is 20 m/s/

Calculate the kinetic energy of the object.

kinetic energy = ................... J [2]

11. Which two forces must be ignored if you assume that an object’s kinetic energy changes by an amount equal to the work done on it by an applied force

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12. Work is done by gravity as an object falls.

The vehicle does not gain the maximum kinetic energy as it falls.

Explain why.

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13. Explain what is meant by the term ‘conservation of energy’

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14. An object drops from a height of 20 m.

It has a mass of 20 kg and weight of 200 N.

Calculate the maximum speed at which the object hits the ground.

Use the idea of transfer between gravitational potential energy and kinetic energy to help you.

maximum speed = ................... m /s [4]