Year 8 Physics: Energy, Forces, Pressure, and Motion Revision

What energy store does a helicopter have when hovering?

The helicopter has gravitational potential energy when hovering above the ground.

What energy store does a helicopter have when it starts to move forwards?

The helicopter has kinetic energy when it starts to move forwards.

What happens to the engine's energy store when it becomes warm?

The engine of the helicopter has thermal energy as it becomes warm.

What energy store does kerosene have?

Kerosene has chemical potential energy.

What happens to a bungee jumper's gravitational potential energy as they fall?

The gravitational potential energy store decreases as they fall.

What happens to a bungee jumper's kinetic energy as they accelerate?

The kinetic energy store increases as they accelerate.

What happens to the elastic potential energy store of a bungee cord when it stretches?

The elastic potential energy store increases as the bungee cord stretches.

What energy store does a battery in a remote-controlled car have?

The battery has chemical potential energy.

What energy store does a remote-controlled car have when it accelerates?

The remote-controlled car has kinetic energy when it accelerates.

What happens to the energy store of a battery when it becomes hot?

The thermal energy store of the battery increases.

What energy store do two charged particles have?

Two charged particles have electric potential energy.

What energy store does uranium fuel have?

Uranium fuel has nuclear potential energy.

What energy store does a chocolate bar have?

A chocolate bar has chemical potential energy.

What energy store do two magnets near each other have?

Two magnets have magnetic potential energy.

What is the equation that links power, energy, and time?

Power = Energy ÷ Time.

What is the unit of power?

The unit of power is the watt (W).

How do you calculate the power of a lamp using 2400 J in 40 s?

Power = 2400 J ÷ 40 s = 60 W.

How do you calculate the power of an electric motor using 4000 J in 200 s?

Power = 4000 J ÷ 200 s = 20 W.

How much energy does a microwave with 900 W use in 15 s?

Energy = Power × Time = 900 W × 15 s = 13500 J.

How much energy does an electric radiator with 2000 W use in 90 s?

Energy = Power × Time = 2000 W × 90 s = 180000 J.

How many watts are in one kilowatt?

There are 1000 watts in one kilowatt.

What is a non-renewable resource?

A non-renewable resource is a resource that cannot be replenished within a human lifetime, such as fossil fuels.

What are the three fossil fuels?

The three fossil fuels are coal, oil, and natural gas.

What is a renewable resource?

A renewable resource is a resource that can be replenished naturally over time, such as solar or wind energy.

What are three examples of renewable resources?

Three examples of renewable resources are solar energy, wind energy, and hydroelectric energy.

Is nuclear power a renewable resource?

No, nuclear power is not a renewable resource.

Does wind power have an unreliable output?

Yes, wind power can have an unreliable output due to varying wind conditions.

Does solar power generate electricity at night?

No, solar power does not generate electricity at night.

What is one disadvantage of burning fossil fuels?

One disadvantage is that burning fossil fuels releases greenhouse gases, contributing to climate change.

What are two uses of fossil fuels other than in power plants?

Fossil fuels are used for transportation and heating.

What are general advantages of using renewable energy resources?

Renewable energy resources are sustainable, reduce greenhouse gas emissions, and decrease dependency on fossil fuels.

What is the initial energy store of water in hydroelectric power?

The initial energy store of water is gravitational potential energy.

What happens to the energy store of water as it falls in hydroelectric power?

The energy is transferred to kinetic energy as the water falls.

What happens to thermal energy in conduction?

Thermal energy is transferred through direct contact between materials.

What are three ways thermal energy can be transferred?

Thermal energy can be transferred by conduction, convection, and radiation.

What happens to atmospheric pressure as we go higher above the Earth's surface?

Atmospheric pressure decreases as we go higher above the Earth's surface.

Which hole in a bottle will water come out faster?

Water will come out faster from the lower hole due to higher pressure.

How do you calculate the pressure exerted by a crate weighing 2600 N with an area of 2 m²?

Pressure = Force ÷ Area = 2600 N ÷ 2 m² = 1300 Pa.

How do you calculate the pressure exerted by a book weighing 20 N with an area of 0.02 m²?

Pressure = Force ÷ Area = 20 N ÷ 0.02 m² = 1000 Pa.

How do you calculate the pressure exerted by a skip weighing 5000 N with an area of 4 m²?

Pressure = Force ÷ Area = 5000 N ÷ 4 m² = 1250 Pa.

How do you calculate the pressure exerted by a person weighing 700 N with an area of 0.04 m²?

Pressure = Force ÷ Area = 700 N ÷ 0.04 m² = 17500 Pa.

Which shoe will sink more in a wet field, a high heel or a trainer?

A high heel shoe will sink more because it has a smaller area, resulting in higher pressure.