Laws Of Motion Question 241
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 N, 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 [AIEEE 2003]
Options:
A) 49 N
B) 24 N
C) 74 N
D) 15 N
Show Answer
Answer:
Correct Answer: B
Solution:
When the lift is stationary $ W=mg $
therefore $ 49=m\times 9.8 $
therefore $ m=5kg. $ When the lift is moving downward with an acceleration $ R=m(9.8-a)=5[9.8-5]=24N $
