Q117 / 150 · MHT CET 2021 (23 Sep Shift 1) · Physics

A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring balance reads $49 \mathrm{~N}$, when the lift is stationary. If the lift moves downward with an acceleration of $5 \mathrm{~m} / \mathrm{s}^2$, the reading of the spring balance will be

  • A
    74 N
  • B
    15 N
  • Correct answer
    C
    24 N
  • D
    49 N

Solution

$\begin{aligned} & \mathrm{W}=49 \mathrm{~N} \\ & \therefore \mathrm{m}=\frac{\mathrm{W}}{\mathrm{g}}=\frac{49}{9.8}=5 \mathrm{~kg} \\ & \mathrm{~W}^{\prime}=\mathrm{W}-\mathrm{ma}=49-5 \times 5=49-25 \\ & =24 \mathrm{~N}\end{aligned}$

Hence, the correct answer is option: 'C'.

Relevant Questions