Question

How fast does a man, weighing 80 kg run so that his kinetic energy is 3240J.​

Answer 1

Given :

Mass of the man = 80KG.

Kinetic energy of the man =3240J.

To find:

Velocity of the Running man=? .

Solution:

The numerical can solved by the following process:

1) Let v be the Velocity with which the man is running.

2) Kinetic energy is given by the formula :

  K.E(KINETIC ENERGY)= 1/2(m$v^{2}$).

3) Since the kinetic energy and mass of the man is given velocity can be found using the above formula.

4) On substitution we get:  

3240=1/2(80*$v^{2}$)        ( since K.E=3240J,m=80KG)

=>v=$\sqrt{81}$m/s.

=>v=9m/s.

(Since all the units are given in S.I units the final answer is also mentioned in the S.I units)

Therefore the Velocity of the running man is 9m/s.