Question

Find the kinetic energy possess by a body of mass 20 kg when it's velocity
changes from 5m/s to 2 m/s?

Answer 1

Answer:

Explanation:

Certain force acting on 20 kg mass changes its velocity from 5 m/s to 2 m/s. Calculate the work done by the force. (KE)2 = (1 )/2 x 20 — (2)2 = 40 J.

Answer 2

Answer:

The kinetic energy possessed by the body is 210J.

Explanation:

The kinetic energy possed by the body will be given as,

$K=\frac{1}{2}m(u^2-v^2)$         (1)

Where,

K=kinetic energy possed by the body

m=mass of the body

u=initial velocity of the body

v=final velocity of the body

From the question we have,

The mass of the body=20kg

Initial velocity of the body(u)=5m/s

Final velocity of the body(v)=2m/s

By substituting the value of m, v, and u in equation (1) we get;

$K=\frac{1}{2}\times 20\times (5^2-2^2)$

$K=10\times (25-4)$

$K=10\times 21$

$K=210J$

Hence, the kinetic energy possessed by the body is 210J.