plz check tis.

work is= ( torque) *( angular displacement)

torque= force *L/2

assumed that force is applied perpendicularly at the edge of the plate

angolar dis after a time t = 0 + (1/2)* a*t^2
a=angular acc
torque =(m.I) * angulatr acc
m.I=moment of inertia of the plate
angular acc =a = torque / (m.I)

sub 4 a in angular displacement.
sub angular diplacement in work formula.

now u get it................

 

theanswer i got is (3/4 * f^2 * t^2 / m)

 

somewhere went wrong?

correct it urself

atleast now plz rate me..............................