Answer to Question #155470 in Physics for jeta

Question

A body with mass m = 100kg makes uniform rectilinear movements in which case it reaches the kinetic energy of Ek = 20 KJ. How fast was it in that case? V =?

Answer 1

The definition of the kinetic energy is:

$$E_k= \dfrac{mv^2}{2}$$

where $m = 100kg$ is the mass of the body, and $v$ is its velocity. Since $E_k = 20kJ = 20\times 10^3J$, obtain for velocity:

$$v = \sqrt{\dfrac{2E_k}{m}}\\ v = \sqrt{\dfrac{2\cdot 20\times 10^3}{100}} = 20m/s$$

Answer. 20 m/s.