Q. A ball of mass is attached to the lower end of light vertical spring of force constant . The upper end of the spring is fixed. The ball is released from rest with the spring at its normal (unstretched) length and comes to rest again after descending through a distance .

Work, Energy and Power Report Error

A

B

C

The ball will have no acceleration at the position where it has descended through .

D

The ball will have an upward acceleration equal to at its lowermost position

Solution:

Apply conservation of energy:
loss in PE of ball = gain in PE of spring

At position :

. So net force is zero. Hence, no acceleration at lowest position:

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