# How to calculate rest energy?

Jul 12, 2022

In order to calculate the rest energy of an object, you will need to know the object’s mass and the speed of light. The speed of light is a constant, so you can plug that value into the equation. The equation for rest energy is:

rest energy = mass x (speed of light)^2

For example, let’s say you want to calculate the rest energy of a person with a mass of 80 kg. The calculation would be:

rest energy = 80 kg x (speed of light)^2

rest energy = 80 kg x (3 x 10^8 m/s)^2

rest energy = 80 kg x 9 x 10^16

rest energy = 720 x 10^16 kg m^2/s^2

The unit of measure for rest energy is the joule, so you can convert the answer to joules by dividing by the speed of light squared.

rest energy (in joules) = 720 x 10^16 kg m^2/s^2 / (3 x 10^8 m/s)^2

rest energy (in joules) = 720 x 10^16 kg m^2/s^2 / 9 x 10^16

rest energy (in joules) = 80 kg

## Other related questions:

### Q: What is rest energy in physics?

A: In physics, the rest energy is the energy that an object has due to its rest mass. The rest energy is the energy of an object at rest, and is equal to the object’s total energy (including kinetic and potential energy) divided by its mass.

### Q: What is formula for rest?

A: There is no definitive answer to this question as different people may have different opinions on what constitutes rest. However, some possible formulas for rest could include taking breaks throughout the day, getting enough sleep at night, and taking time to relax and rejuvenate both physically and mentally.

### Q: How do you find rest energy from kinetic energy?

A: The rest energy is the energy that an object has when it is not moving. The kinetic energy is the energy that an object has when it is moving.

### Q: How do you find the rest mass energy of an electron?

A: The rest mass energy of an electron is found by taking the square of the speed of light and dividing by the rest mass of the electron.