A particle of mass 'm' at rest is acted upon by a force 'P for a time 'r'. Its Kinetic energy after an interval 'r' is:

Options

A. `(p^2t^2)/(m)`
B. `(P^2t^2)/(2m)`
C. `(p^2t^2)/(3m)`
D. `(pt)/(2m)`

Answer

b

Explanation

Here, `K.E.=1/2mv^2=1/2(mv^2)/(mt^2)xxmt^2`
=`1/2(m^2v^2)/(mt^2)xxt^2`
=`1/2(m^2v^2)/(mt^2)xxt^2=1/2(m^2xxa^2xxt^2)/(m)=(P^2xxt^2)/(2m)`
where ma=P= force applied.