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 ?

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

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

In the case of Usain Bolt,

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

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west