A block of mass m is kept on a platform which starts from rest with constant acceleration g/2 upward, as shown in the figure. Work done by normal reaction on block in time t is:

Answers (1)
S safeer

By balancing the forces in vertical direction, we get:

\Rightarrow N-Mg=\frac{Mg}{2}\Rightarrow N=\frac{3mg}{2}

and displacement is given by equation:

s=ut+\frac{1}{2}at^2

where u=0 and a=g/2

\Rightarrow\vec{S}=\frac{1}{2}\vec{\frac{g}{2}}t^{2}

and we know,

W_{N}=\vec{N}.\vec{S}

\Rightarrow W=\frac{3mg^{2}t^2}{8}

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