. A coin is placed on a horizontal platform which undergoes vertical simple harmonic


motion of angular frequency w. The amplitude of oscillation is gradually increased. The coin will leave contact with the platform for the first time

a. at the mean position of the platform

b. for an amplitude of g/w2

c. for an amplitude of g2/w2

d. at the highest position of the platform

Best Answer

Ans || (b)

Solution ||| As the amplitude is increased, the maximum acceleration of the platform along with coin as long as they doesn’t get separated) increases.

a coin placed on a horizontal

Then from Newton’s law, mgN - mw2A

For loosing contact with the platform, N = 0

So, A = g/w2

 

 

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