Question

If momentum of an object is increased by 10% then its kinetic energy will increase by
(1) 20%
(2) 21%
(3) 40%
(4) 19%​

Answer 1

Answer:

(2) 21%

Explanation:

Let the initial mass of the body be m and its velocity be v.

Initial momentum of the body = mv

Initial KE = mv^2/2

If the momentum increases by 10%

,new momentum = mv + 10% of mv

= mv + 10/100mv

= mv + mv/10

=11mv/10

=m(11v/10)

New velocity = 11v/10

Increase in velocity = v/10

New KE = m(11v/10)^2/2

= 121/100mv^2/2

Increase in KE = 21%