Physics Paper 4
Chapter 1 – Motion, Forces, and Energy
1. As the aeroplane decelerates, its kinetic energy decreases.
Suggest what happens to this energy. [1] (0625/41/mj/20)
Kinetic energy is converted into more thermal and sound energy
2. State the name of the form of energy stored in the two springs when they are stretched. [1]
(0625/41/mj/20)
Elastic potential energy
3. When question mentions ‘calculate the density of the liquid in the tube’, atmospheric pressure
should be included. (atmospheric pressure excluded when question mentions ‘pressure caused
by liquid’) (0625/41/mj/20)
4. State and explain which feature of a speed-time graph shows acceleration. [2] (0625/42/mj/20)
- Gradient
- Because gradient = change of speed/time
5. The train took 80s to reduce its speed from 84m/s to 42m/s. Explain why, with the same braking
force, the train takes more than 80s to reduce its speed from 42m/s to zero. [1] (0625/42/mj/20)
Less drag/air resistance at slower speed
6. The drum of the tumble dryer rotates, lifting up the wet clothes which then fall down through
the hot air.
Name the force that causes the clothes to fall down. [1] (0625/42/on/23)
Gravitational force
7. When the drum rotates too fast the clothes remain in contact with the wall of the drum.
State the direction of the resultant force of the clothes during he circular motion. [1]
(0625/42/on/23)
Perpendicular to the motion of clothes
8. Suggest why using a clothesline to dry clothes in the open air is better for the environment than
using an electric tumble dryer. [1] (0625/42/on/23)
- Energy sources not used to generate electricity
- Greenhouse gases not produced
9. Explain in words what is meant by the term ‘impulse’. [1] (0625/42/on/23)
Force x time (for which force acts)
10. Explain how momentum is conserved as the balloon accelerates. [2] (0625/42/on/23)
- Momentum is conserved as air released from the balloon moves in the opposite direction to
the balloon
- Momentum of balloon is equal in size to momentum of air
11. Describe how thermal energy from nuclear reactions is used to generate electricity in a power
station. [3] (0625/42/on/23)
- Thermal energy used to heat water/make steam
,Physics Paper 4
- Steam is at high pressure
- Steam drives a turbine
- Turbine drives a generator
- Turbine moves a coil in a magnetic field
12. State the advantages and disadvantages of using nuclear fuels in a power station instead of
using fossil fuels. [2] (0625/42/on/23)
Advantage:
- Much smaller amount of fuel needed to produce same amount of energy
- No greenhouse gases produced/lower carbon dioxide emissions
- No air pollution
Disadvantage:
- Danger if any leak of radiation
- Produces toxic waste/nuclear waste must be stored for a long time
- Expensive to build nuclear power plant or store nuclear waste
13. Advantages and disadvantages of generating electrical power in nuclear power stations
compared with electrical power generated using wind turbines. [2] (0625/42/fm/23)
Advantage Disadvantage
- Continuous supply of energy - Not renewable
- Produce large amount of energy - Cost of building
- Not affected by weather - Danger of leak of radiation
- Difficulty of storing used radioactive
material/nuclear waste must be stored
for a long time
14. When calculating momentum (mass x velocity), remember to put negative sign when object is
travelling at opposite direction. (0625/43/on/23)
15. When the swimmer is crossing the river, his actions produce a constant forward force on his
body.
Explain why he moves at a constant speed. [2] (0625/41/mj/23)
- Resistance on swimmer backwards
- Balances forward force of swimmer, which leads to no resultant force
16. Describe what happens to the velocity of the motorcyclist as she travels around the bend at
constant speed. [1] (0625/41/mj/23)
Velocity changes as direction of motion changes
17. Explain why there must be a resultant force on the motorcyclist as she travels around the bend.
[2] (0625/41/mj/23)
- Because there is a change in velocity
- Motorcyclist accelerates because direction changes
- Resultant force Is perpendicular to motion of motorcycle
, Physics Paper 4
18. Describe, in terms of the forces acting on the sky-diver, her motion between leaving the balloon
and opening her parachute. [4] (0625/42/on/20)
Two from:
- Weight due to gravity acts down
- Air resistance acts up
- From 0s to 10s, downward force is greater than upward force
- *Resultant force causes acceleration
- *Air resistance increase as speed increases
Two from:
- Initially, acceleration is downwards
- *Acceleration decreases as air resistance increases
- *Terminal velocity reached when upward force equals downward force (constant speed
when air resistance equals weight)
- Terminal velocity reached after about 10s
*from (0625/42/mj/23)
19. The ship is made of steel. The density of steel is 7800kg/m3 and the density of water is
1000kg/m3.
Explain why the ship floats in the water. [2] (0625/42/fm/23)
- There are air spaces in the ship
- Average density of ship is less than density of water
20. Use centre of gravity instead of centre of mass (in most cases). (0625/42/fm/23)
*centre of mass -> doesn’t depend on gravity
21. Principle of conservation of energy. [2] (0625/42/fm/23)
- Energy cannot be created or destroyed
- Energy can be transferred between energy stores
22. As a student catches a cricket ball, she moves her hands backwards.
Chapter 1 – Motion, Forces, and Energy
1. As the aeroplane decelerates, its kinetic energy decreases.
Suggest what happens to this energy. [1] (0625/41/mj/20)
Kinetic energy is converted into more thermal and sound energy
2. State the name of the form of energy stored in the two springs when they are stretched. [1]
(0625/41/mj/20)
Elastic potential energy
3. When question mentions ‘calculate the density of the liquid in the tube’, atmospheric pressure
should be included. (atmospheric pressure excluded when question mentions ‘pressure caused
by liquid’) (0625/41/mj/20)
4. State and explain which feature of a speed-time graph shows acceleration. [2] (0625/42/mj/20)
- Gradient
- Because gradient = change of speed/time
5. The train took 80s to reduce its speed from 84m/s to 42m/s. Explain why, with the same braking
force, the train takes more than 80s to reduce its speed from 42m/s to zero. [1] (0625/42/mj/20)
Less drag/air resistance at slower speed
6. The drum of the tumble dryer rotates, lifting up the wet clothes which then fall down through
the hot air.
Name the force that causes the clothes to fall down. [1] (0625/42/on/23)
Gravitational force
7. When the drum rotates too fast the clothes remain in contact with the wall of the drum.
State the direction of the resultant force of the clothes during he circular motion. [1]
(0625/42/on/23)
Perpendicular to the motion of clothes
8. Suggest why using a clothesline to dry clothes in the open air is better for the environment than
using an electric tumble dryer. [1] (0625/42/on/23)
- Energy sources not used to generate electricity
- Greenhouse gases not produced
9. Explain in words what is meant by the term ‘impulse’. [1] (0625/42/on/23)
Force x time (for which force acts)
10. Explain how momentum is conserved as the balloon accelerates. [2] (0625/42/on/23)
- Momentum is conserved as air released from the balloon moves in the opposite direction to
the balloon
- Momentum of balloon is equal in size to momentum of air
11. Describe how thermal energy from nuclear reactions is used to generate electricity in a power
station. [3] (0625/42/on/23)
- Thermal energy used to heat water/make steam
,Physics Paper 4
- Steam is at high pressure
- Steam drives a turbine
- Turbine drives a generator
- Turbine moves a coil in a magnetic field
12. State the advantages and disadvantages of using nuclear fuels in a power station instead of
using fossil fuels. [2] (0625/42/on/23)
Advantage:
- Much smaller amount of fuel needed to produce same amount of energy
- No greenhouse gases produced/lower carbon dioxide emissions
- No air pollution
Disadvantage:
- Danger if any leak of radiation
- Produces toxic waste/nuclear waste must be stored for a long time
- Expensive to build nuclear power plant or store nuclear waste
13. Advantages and disadvantages of generating electrical power in nuclear power stations
compared with electrical power generated using wind turbines. [2] (0625/42/fm/23)
Advantage Disadvantage
- Continuous supply of energy - Not renewable
- Produce large amount of energy - Cost of building
- Not affected by weather - Danger of leak of radiation
- Difficulty of storing used radioactive
material/nuclear waste must be stored
for a long time
14. When calculating momentum (mass x velocity), remember to put negative sign when object is
travelling at opposite direction. (0625/43/on/23)
15. When the swimmer is crossing the river, his actions produce a constant forward force on his
body.
Explain why he moves at a constant speed. [2] (0625/41/mj/23)
- Resistance on swimmer backwards
- Balances forward force of swimmer, which leads to no resultant force
16. Describe what happens to the velocity of the motorcyclist as she travels around the bend at
constant speed. [1] (0625/41/mj/23)
Velocity changes as direction of motion changes
17. Explain why there must be a resultant force on the motorcyclist as she travels around the bend.
[2] (0625/41/mj/23)
- Because there is a change in velocity
- Motorcyclist accelerates because direction changes
- Resultant force Is perpendicular to motion of motorcycle
, Physics Paper 4
18. Describe, in terms of the forces acting on the sky-diver, her motion between leaving the balloon
and opening her parachute. [4] (0625/42/on/20)
Two from:
- Weight due to gravity acts down
- Air resistance acts up
- From 0s to 10s, downward force is greater than upward force
- *Resultant force causes acceleration
- *Air resistance increase as speed increases
Two from:
- Initially, acceleration is downwards
- *Acceleration decreases as air resistance increases
- *Terminal velocity reached when upward force equals downward force (constant speed
when air resistance equals weight)
- Terminal velocity reached after about 10s
*from (0625/42/mj/23)
19. The ship is made of steel. The density of steel is 7800kg/m3 and the density of water is
1000kg/m3.
Explain why the ship floats in the water. [2] (0625/42/fm/23)
- There are air spaces in the ship
- Average density of ship is less than density of water
20. Use centre of gravity instead of centre of mass (in most cases). (0625/42/fm/23)
*centre of mass -> doesn’t depend on gravity
21. Principle of conservation of energy. [2] (0625/42/fm/23)
- Energy cannot be created or destroyed
- Energy can be transferred between energy stores
22. As a student catches a cricket ball, she moves her hands backwards.
