question_answer

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

A) 24N

B) 74N

C) 15N

D) 49N

Correct Answer: A

Solution :

[a] For the bag accelerating down \[mg-T=ma\] \[\therefore T=m(g-a)\] \[=\frac{49}{10}\left( 10-5 \right)\] \[=24.5\]