Question

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

• A. $24N$
• B. $15N$
• C. $74N$
• D. $49N$

Answer 1

The correct option is A $24N$

• 1.Lift is stationary so mass =$\frac{weight}{g}$ or $\frac{49}{9.8}=5Kg$

so weight when lift is going downward will be decreased due to upward psuedo force and new weight is $mass\times (g-a)=5\times (9.8-5)=24N$

Option A is correct