Laws Of Motion Question 208
Question: A cork is submerged in water by a spring attached to the bottom of a pail. When the pail is kept in a elevator moving with an acceleration downwards, the spring length [EAMCET (Engg.) 1995]
Options:
A)Increases
B) Decreases
C) Remains unchanged
D) Data insufficient
Show Answer
Answer:
Correct Answer: B
Solution:
Density of cork = d, Density of water = r Resultant upward force on cork$ =V(\rho -d)g $ This causes elongation in the spring. When the lift moves down with acceleration a, the resultant upward force on cork$ =V(\rho -d)(g-a) $ which is less than the previous value. So the elongation decreases.
