Energy

A mass of $2.0\,\text{kg}$ has $300\,\text{J}$ of kinetic energy. Determine the speed of the mass.

May/June 2015

A rocket with total mass $M$ is moving at speed $v$. Its engine is switched on and fuel is consumed. The rocket’s mass falls to $\frac{M}{2}$ and its speed rises to $2v$. What happens to the kinetic energy of the rocket?

May/June 2015

A child descends a slide. The child’s weight is 250 N. The slide has a height of 7.0 m. As the child moves down the slide, 1300 J of work is done against friction. What is the change in gravitational potential energy and what is the child’s final kinetic energy?

May/June 2016

In a coal-fired power station, coal is burned, releasing thermal energy (heat). This thermal energy is then used to generate electrical energy. What is the sequence in which the energy moves through the parts of the power station?

May/June 2017

Electricity can be produced from different energy sources.

May/June 2017

A swing is formed by fastening rope loosely to the branch of a tree, as illustrated in Fig. 2.1. A child moves backwards and forwards several times, beginning at the highest point A.

May/June 2017

The diagram shows a fairground ride that is not moving and has four chairs of equal mass. Which chair has the greatest gravitational potential energy?

May/June 2019

An object is raised. Which expression shows the increase in gravitational potential energy of the object?

May/June 2019

What energy transfer occurs in an electric kettle?

May/June 2021

A girl raises an object with mass $1.0\,\text{kg}$ from the floor and places it on a ledge that is $2.0\,\text{m}$ above the floor. How much potential energy does the object gain? [gravitational field strength $g = 10\,\text{N kg}^{-1}$]

May/June 2021

Which device delivers a continuous, steady energy output for the longest period?

May/June 2022

The diagram depicts a candle that is burning. Which energy store is linked to the burning candle?

May/June 2023

A battery is connected in a circuit to light a lamp. What energy store does the battery have?

May/June 2023

Fig. 2.2 depicts a rider using an electric scooter. Inside the scooter are a battery and a motor that turns the rear wheel.

May/June 2023

An object with mass $5.0\,\text{kg}$ is pushed up a slope at a constant speed of $2.0\,\text{m s}^{-1}$. Which calculation is used to find the change in gravitational potential energy between the bottom and the top?

May/June 2024

Fig. 3.1 illustrates a solar-powered charger linked to a cell phone (mobile phone). The battery inside the cell phone receives charge from the solar-powered charger. Fig. 3.2 presents an energy transfer diagram with boxes labelled: "[blank] energy in Sun" → light from Sun → "electric field in charger" → electrical current → "[blank] energy in battery".

May/June 2024

A stone with mass $20\,\text{kg}$ moves through space at a speed of $6.0\,\text{m s}^{-1}$. What is its kinetic energy?

May/June 2025

If a table tennis ball is released from the position shown in Fig. 4.1, it rises again after the impact. During the bounce, some of the ball’s starting gravitational potential energy (GPE) is transferred away. GPE is calculated with the equation $\text{GPE} = mgh$, where $m$ is the mass of the ball, $g$ is the gravitational field strength and $h$ is the height above the bench from which the ball is released.

May/June 2025

A person launches a stone so that it moves along the path shown in the diagram. At which point does the stone have the greatest gravitational potential energy?

Oct/Nov 2015

Water is carried to a village in a tank that is pulled by a tractor. Fig. 1.1 shows the tank being pulled by a tractor. The total mass of the tractor and the tank is 4100 kg when the tank is empty and 6500 kg when the tank is full of water.

Oct/Nov 2015

A weightlifter raises some masses to a vertical height of $1.8\,\text{m}$. The gravitational field strength $g$ is $10\,\text{N kg}^{-1}$. As the lift takes place, the gravitational potential energy of the masses rises by $4500\,\text{J}$. What is the total mass lifted?

Oct/Nov 2016

Objects $P$, $Q$ and $R$ each have different masses and different speeds, as given in the table. In what order do they have increasing kinetic energy (smallest first)?

Oct/Nov 2016

Three objects P, Q and R each have different masses and different speeds, as listed in the table. Masses: $P = 1.0\,\text{kg}$, $Q = 2.0\,\text{kg}$, $R = 5.0\,\text{kg}$. Speeds: $P = 3.0\,\text{m s}^{-1}$, $Q = 2.0\,\text{m s}^{-1}$, $R = 1.0\,\text{m s}^{-1}$. In what order should the objects be placed for increasing kinetic energy (smallest first)?

Oct/Nov 2016

An astronaut on the Moon lets go of a tool box with mass $3.0\,\text{kg}$. It starts from rest, and when it strikes the surface its kinetic energy is $0.96\,\text{J}$. With what speed does the tool box strike the Moon’s surface?

Oct/Nov 2017

A tennis ball with mass $56\,\text{g}$ is moving at $1500\,\text{metres per minute}$. Which expression is equivalent to the kinetic energy, in joules, of the tennis ball?

Oct/Nov 2017

The diagram shows a geothermal power station. Which useful energy transformation is occurring?

Oct/Nov 2018

A rock from space is moving rapidly towards the Earth.

Oct/Nov 2018

A student carries out an experiment using a glass ball and a metal ball. Fig. 2.1 presents the apparatus he uses. The glass ball is put on a cloth-covered bench at the base of a slope. The metal ball is then let go from the top of the slope. It travels down the slope and then collides with the glass ball.

Oct/Nov 2018

Body $X$ has mass $m$ and speed $v$. A second body, $Y$, has mass $2m$ and speed $2v$. Determine the ratio $\frac{\text{kinetic energy of }Y}{\text{kinetic energy of }X}$.

Oct/Nov 2019

A small coin with mass $m$ starts from rest. It is released from a height $h$ above the ground. Its speed is $v$ when it reaches the ground. The gravitational field strength $g$ is $10\,\text{N kg}^{-1}$.

Oct/Nov 2019

A ball is released from the height shown. If air resistance is ignored, which statement about the ball’s total energy is correct?

Oct/Nov 2020

A ball is released from a height as illustrated. If air resistance is ignored, which statement about the ball’s total energy is correct?

Oct/Nov 2020

In a coal-fired power station, coal is burned and electrical energy is generated.

Oct/Nov 2021

This child’s toy is made up of a flexible track and a model car. Fig. 2.1 is a diagram of the toy. At first, the child holds the car still at point A, which is 0.45 m above the horizontal parts of track BC and FG. The car has a mass of 0.12 kg. The child then lets the car go and it moves towards point B. Air resistance and friction between the car and the track are both negligible. The gravitational field strength is 10 N/kg.

Oct/Nov 2022

The diagram depicts a fairground ride at rest, carrying four chairs of equal mass. Which chair has the greatest gravitational potential energy?

Oct/Nov 2023

The diagram depicts a curved track, and a ball is let go from the position indicated. At which point is the gravitational potential energy stored in the ball greatest?

Oct/Nov 2023

A body with mass $5.0\,\text{kg}$ is travelling at steady speed. Its kinetic energy is $10\,\text{J}$. What is the object's speed?

Oct/Nov 2024

In a kettle powered by the mains supply, how is energy transferred?

Oct/Nov 2024

A student shapes a ball from modelling clay. Its mass is 0.20 kg. She releases the ball from 40 m above the ground.

Oct/Nov 2024

Energy is stored in batteries, fuel and food. What is the name of this store of energy?

Oct/Nov 2025