A little platform oscile with a frequency of 4hz and an amplitude of 7 cm, attached to a vertical spring. A small object is poised on the top of the spring in the exactly moment it is in the lowest position. Admit the object is so light that it doesn't change the oscillation perceptively.

A.what is the distance from the equilibrium position of the platform that the object loses contact?

B.the velocity in this instant

(sorry for my bad English. If anyone want to reformulate the question for better understanding, it would be welcome)

Question

A little platform oscile with a frequency of 4hz and an amplitude of 7 cm, attached to a vertical spring. A small object is poised on the top of the spring in the exactly moment it is in the lowest position. Admit the object is so light that it doesn't change the oscillation perceptively.

A.what is the distance from the equilibrium position of the platform that the object loses contact?

B.the velocity in this instant

(sorry for my bad English. If anyone want to reformulate the question for better understanding, it would be welcome)

anonymous · Answer

*a small object is poused/put

anonymous · Answer

at the highest point  when the platform is returning to equilibrium. 
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at highest point velocity of both object and platform will be zero but acceleration of platform will be greater than the object hence it will lose contact there.