Energy Archives - Fridge Physics

Energy

Kinetic Energy

In physics, the kinetic energy (KE) of an object is the energy that it has due to its motion. It is defined as the work needed for an object of a known mass to accelerate to a given velocity.

What is Kinetic energy?

In physics, the kinetic energy (KE) of an object is the energy that it has due to its motion. It is defined as the work needed for an object of a known mass to accelerate to a given velocity.

Kinetic energy equation

To calculate Kinetic energy we write the equation like this.

$E_k = { 1 \over2} mv {^2}$

Kinetic energy demo

In this tutorial you will learn how to calculate the energy stored in a moving object.

Chilled practice question

Copy out the question and attempt to calculate the answer before watching the solution. Write down the equation and show all of your working, remember to add the units to your answer, this routine will guarantee you maximum marks in an exam. Mark your solution and correct if needed.

Calculate the Kinetic energy store in a car with a mass of 850 Kg moving at a velocity of 3.5 m/s.

Frozen practice question

Copy out the question and attempt to calculate the answer before watching the solution. Write down the equation and show all of your working, remember to add the units to your answer, this routine will guarantee you maximum marks in an exam. Mark your solution and correct if needed.

A meteorite has 8000 J of Kinetic energy, calculate its mass if it has a velocity of 20 m/s

Science in context

Anything that is moving has energy in its kinetic energy store.

Millie’s Master Methods

Millie’s Magic Triangle

The ability to rearrange equations is the first step to successfully solve Physics calculations. Millie’s Magic Triangle Teaches you to be confident when transposing an equation allowing …
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Calculation Master Method

Performing and mastering this routine will guarantee you maximum marks when solving Physics calculations. Calculation Master Class Top Mark Routine Applying this technique will ensure you gain …
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Specific Heat Capacity

Specific heat capacity is how much heat energy is required to raise 1 kg of a substance by 1 °C.

What is Specific heat capacity?

Specific heat capacity is how much heat energy is required to raise 1 kg of a substance by 1 °C. Specific heat capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass. The specific heat capacity of a material is a physical property and different materials have a different specific heat capacities.

Specific heat capacity equation

To calculate Specific heat capacity we write the equation like this.

$\Delta E = mc\Delta\theta$

Specific heat capacity demo

In this tutorial you will learn how to calculate how much energy is required to raise the temperature of a known mass of a substance.

Chilled practice question

The specific heat capacity of water is 4200 J/Kg/ °C. Calculate the energy needed to raise 4 Kg of water from 18 °C to 35 °C.

Frozen practice question

Calculate the S.H.C of 750 g of material which needs 14 KJ of heat energy to raise its temperature by 22 °C ?

Science in context

Specific heat capacity is how much heat energy is required to raise 1 kg of a substance by 1 °C.

Millie’s Master Methods

Millie’s Magic Triangle

The ability to rearrange equations is the first step to successfully solve Physics calculations. Millie’s Magic Triangle Teaches you to be confident when transposing an equation allowing …
Start Learning

Calculation Master Method

Performing and mastering this routine will guarantee you maximum marks when solving Physics calculations. Calculation Master Class Top Mark Routine Applying this technique will ensure you gain …
Start Learning

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Power

The quantity power is the rate at which work is done. The quicker work is done the greater the power.

What is Power?

The quantity power is the rate at which work is done. The quicker work is done the greater the power. The standard metric unit of power is the Watt. The calculation of power is the work done in Joules divided by a unit of time seconds. 1 Watt is equivalent to 1 joule of work done per second. Many machines have their power rating displayed upon them in Watts, the higher the value the greater the power of the machine and the faster the rate of energy transfer.

Power equation

To calculate Power we write the equation like this.

$P = { W \over \text{t}} = { E \over \text{t}}$

Power demo

In this tutorial you will learn how to calculate power, the rate of doing work during an energy transfer.

Chilled practice question

Calculate the power of an electric fire if it transfers 950 KJ of energy in 5 minutes 30 seconds.

Frozen practice question

An electric heater has a power rating of 2200 W. How long to the nearest second does it take to transfer 500 KJ of energy.

Science in context

Power is the rate of energy transfer per second.

Millie’s Master Methods

Millie’s Magic Triangle

The ability to rearrange equations is the first step to successfully solve Physics calculations. Millie’s Magic Triangle Teaches you to be confident when transposing an equation allowing …
Start Learning

Calculation Master Method

Performing and mastering this routine will guarantee you maximum marks when solving Physics calculations. Calculation Master Class Top Mark Routine Applying this technique will ensure you gain …
Start Learning

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Elastic Potential Energy

Stretching or squashing an object can transfer energy into its elastic potential energy store.

What is Elastic potential energy?

Stretching or squashing an object can transfer energy into its elastic potential energy store. Elastic energy is the mechanical potential energy stored in the material. Elastic energy occurs when objects are compressed, stretched or deformed.

Elastic potential energy equation

To calculate Elastic potential energy we use this equation.

$E_e = { 1 \over2} ke {^2}$

Elastic potential energy demo

In this tutorial you will learn how to calculate the energy stored in a stretched spring.

Chilled practice question

A spring is stretched 200 cm. The spring has a spring constant of 30 N/M. Calculate the stored elastic potential energy of the stretched spring.

Frozen practice question

Calculate the extension of a spring if it has a stored elastic potential energy of 540 J and a spring constant of 30 N/M.

Science in context

Stretching or squashing an object can transfer energy into its elastic potential energy store.

Millie’s Master Methods

Millie’s Magic Triangle

The ability to rearrange equations is the first step to successfully solve Physics calculations. Millie’s Magic Triangle Teaches you to be confident when transposing an equation allowing …
Start Learning

Calculation Master Method

Performing and mastering this routine will guarantee you maximum marks when solving Physics calculations. Calculation Master Class Top Mark Routine Applying this technique will ensure you gain …
Start Learning

The Fridge Physics Store

Gravitational Potential Energy

Lifting an object in a gravitational field transfers energy into the objects gravitational energy store. Gravitational potential energy is the energy an object has due to its height above Earth.

What is Gravitational potential energy?

Lifting an object in a gravitational field transfers energy into the objects gravitational energy store. Gravitational potential energy is the energy an object has due to its height above Earth. The equation for gravitational potential energy is GPE = mgh, where m is the mass in kilograms, g is the gravitational field strength (9.8 N/Kg on Earth), and h is the height above the ground in meters.

Gravitational potential energy equation

To calculate Gravitational potential energy we use this equation.

$E_p = mgh$

Gravitational potential energy demo

In this tutorial you will learn how to calculate the energy stored in an elevated object.

Chilled practice question

Copy out the question and attempt to calculate the answer before watching the solution. Write down the equation and show all of your working, remember to add the units to your answer, this routine will guarantee you maximum marks in an exam. Mark your solution and correct if needed.

A barrel is lifted onto a shelf 3.5 m from the ground. The barrel has a mass of 22 Kg. Calculate the energy in its G.P.E store.

Frozen practice question

Copy out the question and attempt to calculate the answer before watching the solution. Write down the equation and show all of your working, remember to add the units to your answer, this routine will guarantee you maximum marks in an exam. Mark your solution and correct if needed.

A ski lift transfers 11 KJ of energy into a mans G.P.E energy store. The man has a mass of 55 Kg, calculate the height he was elevated.

Science in context

Lifting an object in a gravitational field transfers energy into the objects gravitational energy store.

Millie’s Master Methods

Millie’s Magic Triangle

The ability to rearrange equations is the first step to successfully solve Physics calculations. Millie’s Magic Triangle Teaches you to be confident when transposing an equation allowing …
Start Learning

Calculation Master Method

Performing and mastering this routine will guarantee you maximum marks when solving Physics calculations. Calculation Master Class Top Mark Routine Applying this technique will ensure you gain …
Start Learning

The Fridge Physics Store

Efficiency

The efficiency of a device is the proportion of input energy that is converted to useful energy.

What is Efficiency?

The efficiency of a device is the proportion of input energy that is converted to useful energy. Efficiency is a measure of how much work or energy is conserved in an energy transfer, work or energy can be lost, for example as wasted heat energy. The efficiency is the useful energy output, divided by the total energy input, and can be given as a decimal always less than 1 or a percentage. No machine is 100% efficient.

Efficiency equation

To calculate Efficiency we use this equation.

$efficiency = {\text{useful energy output} \over\text{total energy input}}$

Efficiency demo

In this tutorial you will learn how to calculate how efficient a device is at transferring energy from one form to another.

Chilled practice question

Calculate the efficiency of a light bulb with a total input energy of 500 J. The bulb emits 200 J of light energy and 300 J of heat energy.

Frozen practice question

A tumble drier is 80% efficient. Its useful energy is 45 KJ what is the total input energy in Joules.

Science in context

The efficiency of a device is the proportion of the total input energy that is converted to useful energy.

Millie’s Master Methods

Millie’s Magic Triangle

The ability to rearrange equations is the first step to successfully solve Physics calculations. Millie’s Magic Triangle Teaches you to be confident when transposing an equation allowing …
Start Learning

Calculation Master Method

Performing and mastering this routine will guarantee you maximum marks when solving Physics calculations. Calculation Master Class Top Mark Routine Applying this technique will ensure you gain …
Start Learning

The Fridge Physics Store

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