A block of mass `m` at rest is acted upon by a force `F` for a time t. The kinetic energy of block after time t is

Options

A. `F^(2) t^(2)//2m`
B. `Ft//2m`
C. `(F^(2))/(2mt^(2))`
D. `t^(2)//2Fm`

Answer

A

Explanation

Kinetic energy `=(1)/(2) mv^(2)= (1)/(2m) (m^(2)v^(2))`
`=(("Momentum")^(2))/(2m)`
Momentum = Impulse
`KE = (("Impluse")^(2))/(2m)= (F^(2) t^(2))/(2m)`
(`because` Impuls = Force `xx` Time = Change in momentum)