Question

Olympic gold medalist usain bolt can run 100 m in roughly 100 kg.A powerful rifle bullet moves at roughly 1000 m/s and has a mass of approximately 10 g. Is the kinetic energy of usain smaller than the kinetic energy of bullet or the same ?

Answer 1

To solve this exercise it is necessary to be clear about the concepts related to the kinetic energy of a body.

The equation of kinetic energy is

`KE = (1)/(2)mv^2`

We will differentiate the two cups and compare the kinetic energies, so

`KE_(bullet) = (1)/(2)(0.01)(1000^2) = 5000J`

In the case of Usain Bolt,

`KE_(Bolt) = (1)/(2) (100)(10.43^2) = 5439J`

We can conclude that the Kinetic Energy of Usain Bolt is bigger than a Bullet.

Note: The current men's world record in 100m is 9.58s, which is equal to a mean velocity of 10.43m/s