Simple harmonic motion: platform

[Kushal]

Homework Statement

A point mass rests on a horizontal platform which can be made to describe vertical s.h.m. of amplitude 0.10m and frequency 2.0 Hz. The mass makes contact with the platform as it rises from its lowest point. At what point, if any, will this contact be lost?

Homework Equations

shm equations

The Attempt at a Solution

i'm thinking that this will happen at the top, x = 0.1 m, where after instantaneous zero velocity, the platform will be attracted to a larger extent downwards than the particle. but then the answer is x = 62 mm. i don't understand.

 

[Kurdt]

For this problem you will have to find the point where the harmonic oscillator accelerates faster than the acceleration due to gravity. What do you know about SHM and acceleration?