Question

A coin is placed on a horizontal platform, which undergoes vertical simple harmonic motion of angular frequency ω. The amplitude of oscillation is gradually increased. The coin will leave contact with the platform for the first time.

(a) For an amplitude of g^2/ω^2

(b) For an amplitude of g/ω^2

(c) At the highest position of the platform

(d) At the mean position of the platform

This question was addressed to me by my school principal while I was bunking the class.

I'm obligated to ask this question of Harmonic Motion topic in section Oscillations of Engineering Physics I

Answer 1

The correct option is (b) For an amplitude of g/ω^2

To explain: The coin will remain in contact with the platform if amax  does not exceed g, that is amax is at the most equal to g.

amax=g

aω^2=g

a=g/ω^2.