GCSE Physics Revision: 5) Forces Part 1 V1

Q1.

This question is about forces.

(a)Force is a vector quantity.

Which is a correct statement about a vector quantity?

Tick one box.

Has direction only /
Has direction and magnitude /
Has magnitude only /
Has neither magnitude nor direction /

(1)

(b)A newtonmeter measures the weight of an object.

Look at the figure below.

What is the weight of the object in the figure above?

Weight = ______N

(1)

(c)An object has a weight of 6.4 N.

Calculate the mass of the object.

Use the equation

mass = weight ÷ gravitational field strength (g)

gravitational field strength = 9.8 N / kg

______

Mass = ______kg

(1)

(d)The mass of a bag of sugar is 1 kg.

•On Earth the weight of this bag of sugar is 10 N.

•On Mars the weight of this bag of sugar is 4 N.

Suggest why the weight of the bag of sugar is different on Earth and on Mars.

______

(1)

(Total 4 marks)

Q2.

The diagram shows a worker using a constant force of 60 N to push a crate across the floor.

My Revision Notes AQA GCSE Physics for A* – C,
Steve Witney, © Philip Allan UK

(a) The crate moves at a constant speed in a straight line

(i)Draw an arrow on the diagram to show the direction of the friction force
acting on the moving crate.

(1)

(ii) State the size of the friction force acting on the moving crate.

______N

Give the reason for your answer.

______

(2)

(b) Calculate the work done by the worker to push the crate 28 metres.

Show clearly how you work out your answer and give the unit.

Choose the unit from the list below.

joule / newton / watt

______

Work done = ______

(3)

(Total 6 marks)

Q3.

The diagram shows a climber part way up a cliff.

(a) Complete the sentence.

When the climber moves up the cliff, the climber

gains gravitational ______energy.

(1)

(b) The climber weighs 660 N.

(i)Calculate the work the climber must do against gravity, to climb to the top of the cliff.

______

Work done = ______J

(2)

(ii)It takes the climber 800 seconds to climb to the top of the cliff.
During this time the energy transferred to the climber equals the work done by the climber.

Calculate the power of the climber during the climb.

______

Power = ______W

(2)

(Total 5 marks)

Q4.

A student investigates rolling a marble down a track.

The figure below shows how he sets up the investigation.

The student lets go of the marble from different heights.

He records:

•the height from which he drops the marble (the drop height)

•the height the marble rolls up the other side (the roll height).

(a)What force causes the marble to fall down the track?

Tick one box.

Air resistance /
Friction /
Gravity /
Magnetism /

(1)

(b)What is one variable the student should control in the investigation?

Tick one box.

Length of ruler /
Length of track /
Mass of marble /
Roll height /

(1)

(c)The table below shows the student’s results.

Drop height
in cm / Roll height in cm
Test 1 / Test 2 / Test 3 / Mean
20 / 15 / 14 / 14 / 14
40 / 29 / 33 / 32
60 / 47 / 19 / 46 / 46
80 / 65 / 61 / 63 / 63

What is the independent variable in the investigation?

Tick one box.

Drop height /
Length of track /
Mass of marble /
Roll height /

(1)

(d)Calculate the mean roll height of the marble when it is dropped from 40 cm.

______

Mean roll height = ______cm

(1)

(e)The student calculated the mean roll height for a drop height of 60 cm.

He did not include the result for Test 2 in his calculation.

Why did the student leave out the result for Test 2?

______

(1)

(f)Describe how the drop height of the marble affects the roll height.

______

(1)

(g)Why does the marble never roll up to the same height the student drops it from?

______

(1)

(Total 7 marks)

Q5.

Forces can be classed as contact or non-contact forces.

(a)Look at the table below.

Tick one box for each type of force to say whether it is a contact force or a non-contact force.

Type of force / Contact force / Non-contact force
Electrostatic
Friction
Gravity

(3)

(b)Force is a vector quantity.

What are two other vector quantities?

Tick two boxes.

Mass /
Time /
Velocity /
Speed /
Displacement /

(2)

(c)A student does a practical to investigate the relationship between force and extension for a spring.

Figure 1 shows how he set up his experiment.

Figure 1

What could the student do to improve the accuracy of his investigation?

Tick one box.

Use a longer ruler to measure the length /
Use a pointer from the spring to measure the length /
Use a new spring between each reading /
Use a stronger spring in the investigation /

(1)

(d)The weight on the spring is the force applied to the spring.

The student puts a mass of 25 g on the spring.

Gravitational field strength = 9.8 N / kg

Calculate the weight on the spring.

Use the equation:

weight = mass × gravitational field strength

______

Weight on spring = ______N

(3)

(e)The student plotted a graph of force applied and extension of the spring.

Figure 2 shows his graph.

Figure 2

What is the relationship between force applied and extension?

Tick one box.

Extension is directly proportional to force /
Extension increases by smaller values as force increases /
Extension is inversely proportional to force /

(1)

(f)Use Figure 2 to determine the force needed to give an extension of 4.5 cm.

Force needed = ______N

(1)

(g)A different spring has a spring constant of 13.5 N / m.

Calculate the elastic potential energy stored in the spring when its extension is 12 cm.

Use the correct equation from the Physics equation sheet.

______

Elastic potential energy = ______J

(2)

(Total 13 marks)

Q6.

A student investigated the behaviour of springs. She had a box of identical springs.

(a)When a force acts on a spring, the shape of the spring changes.

The student suspended a spring from a rod by one of its loops. A force was applied to the spring by suspending a mass from it.

Figure 1 shows a spring before and after a mass had been suspended from it.

Figure 1

Before / After

(i)State two ways in which the shape of the spring has changed.

1. ______

2. ______

(2)

(ii)No other masses were provided.

Explain how the student could test if the spring was behaving elastically.

______

(2)

(b)In a second investigation, a student took a set of measurements of force and extension.

Her results are shown in Table 1 .

Table 1

Force in newtons / 0.0 / 1.0 / 2.0 / 3.0 / 4.0 / 5.0 / 6.0
Extension in cm / 0.0 / 4.0 / 12.0 / 16.0 / 22.0 / 31.0

(i)Add the missing value to Table 1.

Explain why you chose this value.

______

(3)

(ii)During this investigation the spring exceeded its limit of proportionality.

Suggest a value of force at which this happened.

Give a reason for your answer.

Force = ______N

Reason ______

______

(2)

(c)In a third investigation the student:

•suspended a 100 g mass from a spring

•pulled the mass down as shown in Figure 2

•released the mass so that it oscillated up and down

•measured the time for 10 complete oscillations of the mass

•repeated for masses of 200 g, 300 g and 400 g.

Figure 2

Her results are shown in Table 2.

Table 2

Time for 10 complete oscillations in seconds
Mass in g / Test 1 / Test 2 / Test 3 / Mean
100 / 4.34 / 5.20 / 4.32 / 4.6
200 / 5.93 / 5.99 / 5.86 / 5.9
300 / 7.01 / 7.12 / 7.08 / 7.1
400 / 8.23 / 8.22 / 8.25 / 8.2

(i)Before the mass is released, the spring stores energy.

What type of energy does the spring store?

Tick () one box.

Tick ()
Elastic potential energy
Gravitational potential energy
Kinetic energy

(1)

(ii)The value of time for the 100 g mass in Test 2 is anomalous.

Suggest two likely causes of this anomalous result.

Tick () two boxes.

Tick ()
Misread stopwatch
Pulled the mass down too far
Timed half oscillations, not complete oscillations
Timed too few complete oscillations
Timed too many complete oscillations

(2)

(iii)Calculate the correct mean value of time for the 100 g mass in Table 2.

______

Mean value = ______s

(1)

(iv)Although the raw data in Table 2 is given to 3 significant figures, the mean values are correctly given to 2 significant figures.

Suggest why.

______

(2)

(v)The student wanted to plot her results on a graph. She thought that four sets of results were not enough.

What extra equipment would she need to get more results?

______

(2)

(Total 17 marks)

Q7.

The London Eye is one of the largest observation wheels in the world.

©Angelo Ferraris/Shutterstock

The passengers ride in capsules. Each capsule moves in a circular path and accelerates.

(a) Explain how the wheel can move at a steady speed and the capsules accelerate at the same time.

______

(2)

(b) In which direction is the resultant force on each capsule?

______

(1)

(c) The designers of the London Eye had to consider three factors which affect the resultant force described in part (b).

Two factors that increase the resultant force are:

•an increase in the speed of rotation

•an increase in the total mass of the wheel, the capsules and the passengers.

Name the other factor that affects the resultant force and state what effect it has on the resultant force.

______

(1)

(Total 4 marks)

Q8.

This question is about forces, quantities and vectors.

(a)Write down the equation that links gravitational field strength, mass and weight.

______

(1)

(b)A small ball weighs 1.4 N.

gravitational field strength, g = 9.8 N / kg

Calculate the mass of the ball.

______

Mass = ______kg

(3)

(c)A white ball with mass 143 g is moving at a velocity of 7.9 m / s.

It collides with a red ball with mass of 150 g.

The red ball is stationary before the collision. The white ball stops after the collision.

Calculate the velocity of the red ball after the collision.

Give your answer to two significant figures.

______

Velocity of red ball = ______m / s

(4)

(d)The white ball is thrown high into the air.

After it is released the ball moves up and then back down in a vertical line.

The free body force diagram in the figure below shows the forces on the ball at one point in its flight.

The force arrows are drawn to scale.

Explain what is happening to the ball at this point in its flight.

______

(4)

(Total 12 marks)

GCSE Physics Revision: 5) Forces Part 1 V1

Mark schemes

Q1.

(a) Has direction and magnitude

(b) 5.5

(d) the Earth’s gravitational field strength is 2.5 times greater

allow the gravitational field strength on Earth is greater than on Mars

[4]

Q2.

(a)(i) horizontal arrow pointing to the left

judge by eye

drawn anywhere on the diagram

(ii) 60 (N)

(at steady speed) resultant force must be zero

accept forces must balance/are equal

accept no acceleration

do not accept constant speed

(b)1680

allow 1 mark for correct substitution, ie 60 x 28 provided no subsequent step shown

joule

accept J
do not accept j

[6]

Q3.

(a)potential

(b) (i)13 200

allow 1 mark for correct substitution, ie 660 × 20 provided no subsequent step shown

(ii)16.5

allow 1 mark for correct

correctly calculated

substitution, ieor

provided no subsequent step shown

[5]

Q4.

(a) Gravity

(b) Mass of marble

(d) 31 (cm)

(e) the result was anomalous

allow the result was too different from the other values

(f) increasing the drop height increases the roll height

(g) energy losses (due to friction)

allow air resistance, friction, drag

[7]

Q5.

(a)

contact / non-contact
Electrostatic / ✔
Friction / ✔
Gravity / ✔

one mark for each correct tick

(b) Velocity

Displacement

(d) 25 g = 0.025 kg

weight = 0.025 × 9.8

= 0.25 (N)

allow 0.25 with no working shown for 3 marks

(e) Extension is directly proportional to force

(f) 1.125 (N)

allow values between 1.12 and 1.15

(g) elastic potential energy = 0.5 × 13.5 × (0.12)2

= 0.097 (J)

allow 0.097 with no working shown for 2 marks

[13]

Q6.

(a) (i)any two from:

•length of coils increased

•coils have tilted

•length of loop(s) increased

•increased gap between coils

•spring has stretched / got longer

•spring has got thinner

(ii)remove mass

accept remove force / weight

observe if the spring returns to its original length / shape (then it is behaving elastically)

(b) (i)8.0 (cm)

extension is directly proportional to force (up to 4 N)

for every 1.0 N extension increases by 4.0 cm (up to 4 N)

evidence of processing figures eg 8.0 cm is half way between 4.0 cm and 12.0 cm

allow spring constant (k) goes from to

(ii)any value greater than 4.0 N and less than or equal to 5.0 N

the increase in extension is greater than 4 cm per 1.0 N (of force) added

dependent on first mark

(ii)misread stopwatch

timed too many complete oscillations

(iii)4.3 (s)

accept 4.33 (s)

(iv)stopwatch reads to 0.01 s

reaction time is about 0.2 s
or
reaction time is less precise than stopwatch

(v)use more masses

smaller masses eg 50 g

not exceeding limit of proportionality

[17]

Q7.

(a) any two from:

•(acceleration occurs when) the direction (of each capsule) changes

•velocity has direction

•acceleration is (rate of) change of velocity

(b) to(wards) the centre (of the wheel)

accept ‘the size’ for radius
both parts required for the mark

[4]

Q8.

(a)weight = mass × gravitational field strength

(b) mass = weight ÷ g

= 1.4 ÷ 9.8

= 0.143 (kg)

allow 0.143 with no working shown for 3 marks

momentum before = momentum after

143 × 7.9 = 150 × v

v =

= 7.5 (m / s)

allow 7.5 (m / s) with no working shown for 4 marks

incorrect number of sig. figs max. 3 marks

(d) ball is falling / moving down

at terminal velocity

air resistance and weight have the same magnitude / size

so no acceleration / constant speed

[12]

GCSE Physics Revision: 5) Forces Part 1 V1

Examiner reports

Q2.

(a)(i) Over three-quarters of students correctly showed the direction of the friction force. Most incorrect responses involved arrows at various angles indicating where this force was being applied between the crate and the floor rather than the direction of its action.

(ii) Just under a third of students scored both marks in this question, the incorrect responses being mostly in terms of the frictional force being zero, half, or twice the pushing force of 60 N.

(b) Most students were able to correctly calculate the numerical answer, but many were unsure of the appropriate unit, with many students incorrectly giving newton as their response.

Q3.

(a)A majority of the students gave the correct answer.

(b) (i)A majority of students scored both marks. However, many incorrect answers showed students multiplying the correct answer by 10 to give a final incorrect answer.

(ii) Over half of the students scored both marks, either using their correct answer to part (b)(i) or by the error carried forward route.

Q6.

(a) (i)Over three-quarters of students correctly described two ways in which a spring changed shape when a mass was suspended from it. Some stated the same thing twice with ‘got longer’ and ‘extended’ or ‘bigger distance between the loops’.

(ii)Nearly three-quarters of students correctly described how the spring could be tested to see if it behaved elastically.

(b) (i)Nearly all students were able to score at least two out of three marks for completing Table 1 with a value of extension and explaining their value.

(ii)Just less than half of the students correctly suggested a value of force at which the spring exceeded its limit of proportionality and gave a reason.

(ii)Less than a third of students gave the correct two reasons out of five stating why a value in Table 2 was anomalous.

(iii)Over four-fifths of students calculated the correct mean value of time in Table 2 leaving out the anomalous value.

(iv)Hardly any students scored a mark where they were asked why raw values of time were given to three significant figures and mean values given to twosignificant figures. Instead of referring to the precision of a stopwatch and comparing this with human reaction time, they thought that it was something to do with making the plotting of a graph easier.

(v)Just under three-quarters of students correctly suggested that extra masses would be needed to get more results, but relatively few stated that that they should be smaller masses eg 50 g. Many of those who scored both marks also correctly referred to the value of force beyond which the spring may no longer behave elastically.

Q7.

(a) Some students gained one mark for the change of direction; only a very small number of the students gained both marks and, of these, most had given all three of the marking points. There were worrying responses about the downward capsules travelling faster than the upwards ones due to gravity.

(b) Half the students gave the correct answer.