How do you find kinetic energy of an object?

Answer 1

If you know the velocity and the mass, you can use the formula: KE = (1/2) x mass x velocity2.

Otherwise, you have do deduce it from other facts. For example, if an object of a

certain mass falls from a certain height, you can calculate that it started with a

certain amount of potential energy, and assume that after it falls, all of the energy

has been converted to kinetic energy.

Another interesting technique that I've seen on TV is used, for example, to measure

the kinetic energy of a bullet shot from a gun. In that case, they shot the bullet

into a block of wood that was suspended from the ceiling by a string. After the

bullet penetrated the wood and stuck inside it, the block swung some distance,

like a pendulum. By photographing it from the side and measuring exactly how far

it swung and how far it lifted, they were able to calculate the speed and kinetic

energy of the bullet.