A plank with a body of mass `m` places on it starts moving straight up according to the law `y=a(1-cos omegat t )`, whee `y` is the displacement from the initial position, `omega =11 s^(-1)`. Find :
(a) the time dependence of the force that the body exerts on the plank if `a=4.0cm,` plot this dependence,
`(b)` the minimum amplitude of oscillation of the plank at which the body starts falling behind the plank,
(c) the amplitude of oscillation of the plank at which the body springs up to a height `h=50cm` relative to the initial position (at the moment `t=0)`.

Answer

`(g)/(Omega^(2))(Omega.sqrt((2h)/(g))-1)`