A horizontal platform vibrate up and down with a simple harmonic motion of amplitude 20 c.m. At what frequency will an object kept on the platform remain just in contact with the platform ? Take `g = 9.81 m//s^(2)`.

Explanation

To solve the problem of determining the frequency at which an object on a vibrating platform remains in contact with it, we can follow these steps:

### Step 1: Understand the Problem
The platform vibrates with simple harmonic motion (SHM) and has an amplitude \( A = 20 \, \text{cm} = 0.2 \, \text{m} \). The object will lose contact with the platform when the normal force acting on it becomes zero.

### Step 2: Analyze Forces at the Highest Point
At the highest point of the platform's motion, the forces acting on the object are:
- The gravitational force downward: \( mg \)
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