The mass of lift is $2000 \mathrm{~kg}$. When the tension in the supporting cable is $28000 \mathrm{~N}$,…

The mass of lift is $2000 \mathrm{~kg}$. When the tension in the supporting cable is $28000 \mathrm{~N}$, then its acceleration is :
  1. $14 \mathrm{~ms}^{-2}$ upwards
  2. $30 \mathrm{~ms}^{-2}$ downwards
  3. $4 \mathrm{~ms}^{-2}$ upwards
  4. $4 \mathrm{~ms}^{-2}$ downwards

Solution

$\begin{aligned} & \Sigma F=m a \\ & \Rightarrow \mathrm{T}-\mathrm{mg}=\mathrm{ma} \\ & \mathrm{a}=\frac{\mathrm{T}-\mathrm{mg}}{\mathrm{m}}=4 \mathrm{~m} / \mathrm{s}^2 \end{aligned}$

Asked in: NEET 2009 (Mains)

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