question_answer

A coin is placed on a horizontal platform which undergoes vertical simple harmonic motion of angular frequency co. 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 \[\frac{g}{{{\omega }^{2}}}\]

C) for an amplitude of\[\frac{g}{{{\omega }^{2}}}\]

D) at the highest position of the platform

Correct Answer: B

Solution :

[b] For block A to move in S.H.M. \[mg-N=m{{\omega }^{2}}x\] where x is the distance from mean position For block to leave contact N = 0 \[\Rightarrow \,mg=m{{\omega }^{2}}x\Rightarrow x=\frac{g}{{{w}^{2}}}\]