**Energy**

In simple terms, energy is the ability to do some work. Work such as lifting a glass of water or holding a cricket bat. It is the capacity to do work. Its unit is measured in a term called joules. There are many sorts of energy. Some main kinds are kinetic, nuclear, thermal, and electrical.

**Kinetic energy**

It is the type of energy an object possesses when in motion. Suppose a car is moving. It has kinetic energy. Any moving object possesses kinetic energy. A cricket ball moving in the air contains kinetic energy.

There is a very important equation that all students must learn. Using this equation, the kinetic energy of any moving body can be found. Kinetic energy = ½ mv^{2 }(½ x m x v squared) . Mass is denoted by m, and velocity is denoted by v.

Let’s do some mathematics relating to kinetic energy.

Suppose a ball is moving with a velocity of 6 m/s and its mass is 2 kilograms. What is the kinetic energy it possesses? Putting the values into the equation, KE = ½ x 2 x 6^{2} = 36 joules.

Suppose a knife is moving with a velocity of 5 m/s and its mass is 1 kilogram. What is the kinetic energy it possesses? Putting the values into the equation, KE = ½ x 1 x 5^{2} = 12.5 joules

Suppose a plane is moving with a velocity of 100 m/s, and its mass is 2000 kilograms. What is the kinetic energy it possesses? Putting the values into the equation, KE = ½ x 2000 x 100^{2} = 100000000 joules.

Suppose a boy is moving with a velocity of 9 m/s, and his mass is 60 kilograms. What is the kinetic energy it possesses? Putting the values into the equation, KE = ½ x 60 x 9^{2} = 2430 joules.