Question

A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring 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. 49 N
• B. 24 N
• C. 74 N
• D. 15 N

Hint:

In a downward accelerating lift, apparent weight = $m(g - a)$.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Apparent weight changes in an accelerating lift.
Step 2: Detailed Explanation:
When stationary, $mg = 49$ N, so $m = 5$ kg. When lift moves downward with acceleration $a$, apparent weight = $m(g - a) = 5(9.8 - 5) = 5 \times 4.8 = 24$ N.
Step 3: Final Answer:
The reading will be 24 N.