A block of mass m is kept in an elevator whic | vedclass

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(B) Observer $B$ is on the ground (inertial frame).For observer $B$,the block moves downward with acceleration $a$.The forces acting on the block are

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$\frac{1}{2}m{a^2}t_0^2$

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(B) Observer $B$ is on the ground (inertial frame).For observer $B$,the block moves downward with acceleration $a$.The forces acting on the block are gravity ($mg$ downwards) and the normal force ($N$ upwards).From the equation of motion: $mg - N = ma$,so $N = m(g - a)$.The net force on the block is $F_{net} = mg - N = ma$ (downwards).The displacement of the block in time $t_0$ is $s = \frac{1}{2}at_0^2$ (downwards).The net work done on the block according to observer $B$ is $W = F_{net} \cdot s = (ma) \cdot (\frac{1}{2}at_0^2) = \frac{1}{2}ma^2t_0^2$.

$A$ block of mass $m$ is kept in an elevator which starts moving downward with an acceleration $a$ as shown in the figure. The block is observed by two observers $A$ and $B$ for a time interval $t_0$. According to observer $B$,the net work done on the block is

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