3. If a bullet having the mass of 50 g is fired at the velocity of 200km per hour, how much kinetic energy does it have?

77.3J

Explanation:

Given parameters:

Mass of the bullet  = 50g  = 0.05kg

Velocity of the bullet  = 200km/hr

Unknown:

Kinetic energy of the bullet  = ?

Solution:

Kinetic energy is the energy due to motion of a body.

It is mathematically expressed as;

        K.E  = m v²

m is the mass

v is the velocity

 we need to convert the velocity to m/s

  200km/hr is 55.6m/s

Input the parameters and solve;

 K.E = x 0.05 x 55.6²  = 77.3J

this would be about 43%