A particle is moving on y axis under a varible force `F= - ky + C`.
If in part (a) `F= - 10y + 20`, and mass m of the particle is 2.5kg and it is released from rest from `y = +3`, at t= 0, write the equation of SHM.

Explanation

To solve the problem step by step, we need to derive the equation of Simple Harmonic Motion (SHM) for the given force acting on a particle.

### Step 1: Identify the force and mass
We are given the force acting on the particle as:
\[ F = -10y + 20 \]
The mass \( m \) of the particle is given as:
\[ m = 2.5 \, \text{kg} \]

...