Question
A block of mass $m$ is suspended by a light thread from an elevator. The elevator is accelerating upward with uniform acceleration $a$ . The work done by tension on the block during $t$ seconds is $(u = 0)$
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Answer
$\mathrm{T}=\mathrm{mg}+\mathrm{ma}, \quad \mathrm{S}=\frac{1}{2} \mathrm{at}^{2}$
$\mathrm{W}_{\mathrm{T}}=\mathrm{T} \times \mathrm{S}$
$=\frac{\mathrm{m}(\mathrm{g}+\mathrm{a}) \mathrm{at}^{2}}{2}$
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