Edexcel IGCSE Physics Forces and Momentum

[Maximum number: 7]

The diagram shows a child's toy for accelerating steel balls.

Figure for Question 1 — Edexcel IGCSE Physics

This is how the toy works.
- the toy uses three identical steel balls, each with a mass of 4.1 g
- ball A moves towards the magnet
- ball B is in contact with the magnet
- balls B and C are initially at rest and are in contact with each other
- when ball A collides with the magnet, ball C moves away from the magnet

(a)

Ball A moves towards the magnet with an initial velocity of 0.15 m/s.

Calculate the initial momentum of ball A.

initial momentum = ............ kg m/s

[ 2 ]

(b)

Ball A is attracted to the magnet.

Explain how this attraction affects the momentum of ball A as it approaches the magnet.

[ 2 ]

(c)

When ball A collides with the magnet, a force of 1.3 N is exerted on ball C for a time of 0.0025 s.

This causes ball C to move away from the magnet.

Calculate the change in velocity of ball C due to this force.

change in velocity = ............ m/s

[ 3 ]

[Maximum number: 5]

A ship floats on the sea.

Figure for Question 2 — Edexcel IGCSE Physics

(a)

The ship floats because of the forces acting on it.

[ 5 ]

(i)

The upward force acting on the ship is called upthrust.

This force is shown on the diagram.
Draw another labelled arrow on the diagram to show the other vertical force acting on the ship.

[ 2 ]

(ii)

Forces are vector quantities.

State what is meant by the term vector quantity.

[ 2 ]

(iii)

Give another example of a vector quantity.

[ 1 ]

[Maximum number: 4]

The photograph shows a whale jumping out of the surface of the sea.

Figure for Question 3 — Edexcel IGCSE Physics

(a)

A resultant force causes the whale to slow down when it hits the surface of the sea.

[ 4 ]

(i)

Draw an arrow to show this resultant force.

Figure for Question (i) — Edexcel IGCSE Physics

[ 1 ]

(ii)

The resultant force acting on the whale is 18000 N.

The mass of the whale is 4100 kg.

Calculate the acceleration of the whale.

acceleration = ............ m/s^2

[ 3 ]

[Maximum number: 2]

The diagram shows a child's toy for accelerating steel balls.

Figure for Question 4 — Edexcel IGCSE Physics

This is how the toy works.
- the toy uses three identical steel balls, each with a mass of 4.1 g
- ball A moves towards the magnet
- ball B is in contact with the magnet
- balls B and C are initially at rest and are in contact with each other
- when ball A collides with the magnet, ball C moves away from the magnet

Ball A is attracted to the magnet.

Explain how this attraction affects the momentum of ball A as it approaches the magnet.

[Maximum number: 2]

A ship floats on the sea.

Figure for Question 5 — Edexcel IGCSE Physics

The ship floats because of the forces acting on it.

The upward force acting on the ship is called upthrust.

This force is shown on the diagram.
Draw another labelled arrow on the diagram to show the other vertical force acting on the ship.

[Maximum number: 1]

The photograph shows a whale jumping out of the surface of the sea.

Figure for Question 6 — Edexcel IGCSE Physics

A resultant force causes the whale to slow down when it hits the surface of the sea.

Draw an arrow to show this resultant force.

[Maximum number: 2]

Diagram 1 shows a wooden plank balanced horizontally on two supports, A and B.
A block is suspended from the plank between the supports by a cable of negligible weight.

Diagram 1

Diagram 2 shows the block and the cable connecting the block to the plank.

Figure for Question 7 — Edexcel IGCSE Physics

The block also experiences a force due to the tension in the cable.

Explain why the block remains stationary when it is supported by this tension force.

[Maximum number: 3]

Ice hockey is a team sport played on ice. Players try to hit a disc called a puck into the other team's goal.

Figure for Question 8 — Edexcel IGCSE Physics

(a)

Diagram 2 shows a puck travelling across some rough ice.

Diagram 2

The rough ice exerts a frictional force on the puck.

[ 3 ]

(i)

Draw a labelled arrow on diagram 2 to show the force of friction acting on the puck.

[ 1 ]

(ii)

Explain how the force of friction changes the velocity of the puck.

[ 2 ]

[Maximum number: 5]

Diagram 1 shows some apparatus used to demonstrate the magnetic force on a current-carrying wire in a magnetic field.

Diagram 1

The wire has a mass of 6.5 g .

There is an upwards magnetic force of 34 mN acting on the wire.

Calculate the acceleration of the wire.
acceleration = $\mathrm{m} / \mathrm{s}^{2}$

Marking points:
- resultant force is the difference between weight and magnetic force
- resultant force = $31\ \mathrm{mN}$
- substitution into F=ma
- rearrangement
- evaluation

Example:
$F_{\mathrm{resultant}}=65-34=31\ \mathrm{mN}$ $31\times10^{-3}=6.5\times10^{-3}a$ $a=\frac{31\times10^{-3}}{6.5\times10^{-3}}=4.8\ \mathrm{m}\,\mathrm{s}^{-2}$
Allow ECF from (b)(i). Accept $4.57\ \mathrm{m}\,\mathrm{s}^{-2}$ when $g=9.81\ \mathrm{m}\,\mathrm{s}^{-2}$ is used.
POT error gives a 1 mark penalty.
5.2(3) scores 3 MAX when there is no evidence of the resultant-force idea.

[Maximum number: 2]

Diagram 1 shows the apparatus a student uses to investigate the bending of a wooden strip.

Part of the wooden strip is clamped to a table.
A load is fixed to the free end of the wooden strip, causing it to bend.

Diagram 1

The free end of the wooden strip is positioned a length, L , beyond the edge of the table, as shown in diagram 1.

The weight of the load causes the end of the wooden strip to move down through a height, h.

A student investigates how the length, L , affects the height, h .

The load has a mass of 250 g.

Calculate the weight of the load.
Use the formula

weight = mass x gravitational field strength, g

weight = ............ N

Marking points:
- substitution into formula
- evaluation

Example:
W=mg $W=\frac{250}{1000}\times10$ $W=2.5\ \mathrm{N}$

Accept:
- use of g=9.8 or 9.81
- 2.45 or $2.4525\ \mathrm{N}$

Ignore:
- units

Marking guidance:
- Deduct 1 mark for a clear power-of-ten error in units of mass.

[Maximum number: 3]

The graph shows how the thinking distance and the braking distance vary with the speed of a car.

Figure for Question 11 — Edexcel IGCSE Physics

Determine the stopping distance of the car when the speed of the car is 20 m/s.

stopping distance = ............ m

idea that stopping distance = thinking distance + braking distance;

correct reading of either distance;

correct evaluation;

e.g.

stopping distance = thinking distance + braking distance

thinking distance $=10.0 \mathrm{~m} /$ braking distance $=26.5 \mathrm{~m}$

stopping distance $=(10.0+26.5)=36.5(\mathrm{~m})$

stated or implied

allow 26.0-27.0 (m) for braking distance allow 10.0-10.5 (m) for thinking distance allow 36.0-37.5 (m)

[Maximum number: 2]

The graph shows how the thinking distance and the braking distance vary with the speed of a car.

Figure for Question 12 — Edexcel IGCSE Physics

(a)

Which of these does not affect thinking distance?

A

alcohol consumed by the driver

B

condition of the road

C

speed of the car

D

tiredness of the driver

[ 1 ]

(b)

Which of these would increase the braking distance of the car?

A

faster reaction time of driver

B

ice on the road

C

more powerful brakes

D

tyres with more grip

[ 1 ]

[Maximum number: 5]

A student stretches a rubber band.

The student stretches the rubber band and then releases it. The band moves vertically upwards.

The band reaches its maximum height.

Explain the motion of the band as it falls from its maximum height to the ground.

Refer to forces in your answer.
You may assume
- the band does not rotate
- the band does not reach terminal velocity

[Maximum number: 5]

A student investigates how the extension of a spring varies when the mass attached to the spring is changed.

The diagram shows most of the equipment the student uses in the investigation.

Figure for Question 14 — Edexcel IGCSE Physics

Describe a method the student could use for the investigation.
Your description should include the measurements taken and how the student could obtain accurate results.

[Maximum number: 1]

A student stretches a rubber band.

The diagram shows a force-extension graph for a rubber band.

Figure for Question 15 — Edexcel IGCSE Physics

State how the graph shows that the rubber band does not obey Hooke's law.

[Maximum number: 2]

A student stretches a rubber band.

The diagram shows a force-extension graph for a rubber band.

Figure for Question 16 — Edexcel IGCSE Physics

Explain how the graph shows that the rubber band is elastic.

[Maximum number: 2]

The diagram shows a child's toy for accelerating steel balls.

Figure for Question 17 — Edexcel IGCSE Physics

This is how the toy works.
- the toy uses three identical steel balls, each with a mass of 4.1 g
- ball A moves towards the magnet
- ball B is in contact with the magnet
- balls B and C are initially at rest and are in contact with each other
- when ball A collides with the magnet, ball C moves away from the magnet

Ball A moves towards the magnet with an initial velocity of 0.15 m/s.

Calculate the initial momentum of ball A.

initial momentum = ............ kg m/s

[Maximum number: 3]

This question is about momentum.

A child drops an egg from a height of 10 cm and the egg lands on the floor.

Explain why the egg is less likely to break if the floor is covered with a thick carpet than if the floor were covered in hard tiles.

[Maximum number: 4]

This question is about momentum.

(a)

The diagram shows an object before and after an explosion.

The object breaks into two parts, P and Q .
The parts move away from each other in opposite directions.

Figure for Question (a) — Edexcel IGCSE Physics

[ 4 ]

(i)

State what is meant by the principle of conservation of momentum.

[ 1 ]

(ii)

Calculate the magnitude of the velocity of part P after the explosion.

velocity = ............ m/s

[ 3 ]

Marking points:
- setting up equation using conservation of momentum
- rearrangement
- evaluation

Example:
$0=(1.9\times3.7)+(2.9v)$ $1.9\times3.7=2.9v$ $v=\frac{-7.03}{2.9}=-2.4\ \mathrm{m\,s^{-1}}$

Final answer:
$|v|=2.4\ \mathrm{m\,s^{-1}}$

Accept:
- $2.42\ldots\ \mathrm{m\,s^{-1}}$

Marking guidance:
- Ignore the sign of the final answer.
- Correct evaluation of object Q's momentum, i.e. $-7.03\ \mathrm{kg\,m\,s^{-1}}$ , scores 1 mark if no other mark scored.

[Maximum number: 3]

The diagram shows a child's toy for accelerating steel balls.

Figure for Question 20 — Edexcel IGCSE Physics

This is how the toy works.
- the toy uses three identical steel balls, each with a mass of 4.1 g
- ball A moves towards the magnet
- ball B is in contact with the magnet
- balls B and C are initially at rest and are in contact with each other
- when ball A collides with the magnet, ball C moves away from the magnet

When ball A collides with the magnet, a force of 1.3 N is exerted on ball C for a time of 0.0025 s.

This causes ball C to move away from the magnet.

Calculate the change in velocity of ball C due to this force.

change in velocity = ............ m/s

[Maximum number: 2]

A crumple zone is a safety feature in a car.
It is a part of the car that is designed to collapse during a collision.
A student investigates the effectiveness of crumple zones.
The student rolls two model cars down a ramp.
Each car comes to rest when it hits a large metal block.
A data logger measures the mean force applied to the car during the collision with the block.

The diagram shows the equipment used in the investigation.

Figure for Question 21 — Edexcel IGCSE Physics

Car 1 has a paper crumple zone at the front.
Car 2 has no paper crumple zone.
The table shows the student's results.

Table for Question 21 — Edexcel IGCSE Physics

State the magnitude and direction of the force on the metal block, when car 2 collides with the block.
magnitude = N
direction =

[Maximum number: 1]

Diagram 1 shows a wooden plank balanced horizontally on two supports, A and B.
A block is suspended from the plank between the supports by a cable of negligible weight.

Diagram 1

The weight of the block is 260 N .

State the formula linking moment, force and perpendicular distance from the pivot.

[Maximum number: 2]

Diagram 1 shows a wooden plank balanced horizontally on two supports, A and B.
A block is suspended from the plank between the supports by a cable of negligible weight.

Diagram 1

Diagram 2 shows the block and the cable connecting the block to the plank.

Figure for Question 23 — Edexcel IGCSE Physics

The centre of gravity of the block is located at point X .

Draw an arrow on diagram 2 to show the weight of the block.

[Maximum number: 3]

Diagram 1 shows a wooden plank balanced horizontally on two supports, A and B.
A block is suspended from the plank between the supports by a cable of negligible weight.

Diagram 1

The weight of the block is 260 N .

By taking moments about support A, calculate force F.

Assume the weight of the plank is negligible.

force F = ............ N

[Maximum number: 3]

Diagram 1 shows a wooden plank balanced horizontally on two supports, A and B.
A block is suspended from the plank between the supports by a cable of negligible weight.

Diagram 1

The weight of the block is 260 N .

Explain what will happen to the magnitude of force F if the block is moved towards support B.

Edexcel IGCSE Physics C Forces Movement Shape and Momentum Questions

Exam points

Covered syllabus points

Covered syllabus points

Question 1

Question (a)

Question (b)

Question (c)

Question 2

Question (a)

Question (i)

Question (ii)

Question (iii)

Question 3

Question (a)

Question (i)

Question (ii)

Question 4

Question 5

Question 6

Question 7

Question 8

Question (a)

Question (i)

Question (ii)

Question 9

Question 10

Question 11

Question 12

Question (a)

Question (b)

Question 13

Question 14

Question 15

Question 16

Question 17

Question 18

Question 19

Question (a)

Question (i)

Question (ii)

Question 20

Question 21

Question 22

Question 23

Question 24

Question 25