If momentum of an object is increased by 10%, then is kinetic energy will increase by

Options

A. `40%`
B. `20%`
C. `10%`
D. `21%`

Answer

D

Explanation

`(K.E._(2))/(K.E._(1))=(L_(2)^(2))/(L_(1)^(2))`
`= (R_(2)^(2)omega_(2)^(2))/(R_(1)^(2)omega_(1)^(2))=(1.1)^(2)=1.21`
`therefore (K.E._(2))/(K_(.E._(1))-1=1.21-1 therefore K.E._(1)=21%`
`therefore K.E._(2)` increased by 21%.