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WorksheetsY10 C6 Energy Work Power Revision
Total questions: 22
Worksheet time: 12mins
Which motor produces the most power?
heavy load, time taken 12 s
heavy load, time taken 16 s
light load, time taken 12 s
light load, time taken 16 s
An object falls from the top of a building that is 25 m high. Air resistance is negligible. What is the speed of the object when it hits the ground?
10 m/s
22 m/s
25 m/s
625 m/s
A crane takes 2.0 minutes to lift a load to the top of a building. The change in gravitational potential energy of the load is 360 kJ. What is the useful power output of the crane?
3.0 kW
180 kW
720 kW
43200 kW
A force F acts on a body and the body moves a distance d in the direction of the force. Which expression for the work done W is correct?
W = Fd
W = Fd²
W = ½ Fd
W = ½ Fd²
A boy produces an average power output of 60 W as he rides his bicycle for 2.0 minutes. How much useful energy does he expend?
0.50 J
30 J
120 J
7200 J
An object is in free fall. The change in gravitational potential energy of the body depends upon its mass m, the change in height Δh and the gravitational field strength g. What is the correct expression for the change in gravitational potential energy?
gmΔh
gm/Δh
gΔh/m
mΔh/g
What is the unit of power?
joule
newton
pascal
watt
A cyclist travels down a hill from rest at point X without pedaling. The cyclist applies his brakes and the cycle stops at point Y. Which energy transfers have taken place between X and Y?
gravitational potential → kinetic → internal (thermal)
gravitational potential → internal (thermal) → kinetic
kinetic → gravitational potential → internal (thermal)
kinetic → internal (thermal) → gravitational potential
An object of mass m falls from a higher shelf to a lower shelf. How much gravitational potential energy does the object lose?
mgh₂
(m/g)h₂
(m/g)(h₁ - h₂)
mg(h₁ - h₂)
A box is initially at rest at the top of a rough slope. The box slides down the slope. The weight of the box is 20 N. The slope is 4.0 m long and 2.0 m high. The box does 10 J of work against friction as it slides down the slope. What is the speed of the box as it reaches the bottom of the slope?
5.5 m/s
6.3 m/s
7.1 m/s
9.5 m/s
State the principle of conservation of energy.
Energy can be created or destroyed.
Energy can be transformed from one form to another, but the total energy remains constant.
Energy is always increasing in a closed system.
Energy is always decreasing in a closed system.
Suggest one environmental reason for using wind turbines rather than using a diesel (fossil fuel) generator.
Wind turbines produce no greenhouse gas emissions during operation.
Wind turbines are more cost-effective than diesel generators.
Wind turbines require less maintenance than diesel generators.
Wind turbines are easier to install than diesel generators.
Which row about the change of energy in the energy store must be correct?
A
B
C
D
A bicycle braking system transfers energy from a kinetic energy store to an internal energy store. A motor converts energy from a chemical energy store (battery) to a kinetic energy store. What enables these energy transfers?
A
B
C
D
A toy car is pushed a distance of 2.4 m with a force equal to 460 N. How much energy is transferred?
190 J
190 W
1100 J
1100 W
The engine of a motor vehicle develops a large power. Which statement is correct?
The driving force acting on the vehicle must be large.
The engine must have a very large volume.
The engine must transfer large amounts of energy each second.
The vehicle must be very fast.
A woman of mass 50 kg has 81 J of kinetic energy. What is her speed?
1.3 m/s
1.6 m/s
1.8 m/s
3.2 m/s
Which two of these energy resources are non-renewable?
fossil fuels
geothermal power
nuclear fuels
Order the steps in the process to explain how a fossil fuel power station works.
Fossil fuel is burned to release energy.
1
Steam from the boiler turns the turbine.
3
The turbine turns the generator.
4
The energy is used to heat water.
2
The generator produces electricity.
5
Order the steps in the process to explain how a nuclear power station works.
Nuclear fuel releases energy
1
The generator produces electricity
5
The steam turns the turbine
3
The energy is used to heat water until it turns into steam
2
The turbine turns the generator
4
Which two of the following are disadvantages of using nuclear fuels to generate electricity?
Nuclear power stations don't release CO₂ when in use.
Nuclear power stations take a long time to start up.
The nuclear reactor produces radioactive waste, which is dangerous and needs to be stored for a long time.
Which two of the following are advantages of using fossil fuels to generate electricity?
Fossil fuels are easy to extract and transport.
Fossil fuels are concentrated stores of energy.
Fossil fuels release sulfur dioxide (SO₂) when burned, which causes acid rain.
Fossil fuels release carbon dioxide (CO₂) when burned, which contributes to global warming.
