This question already has an answer here:
- Explanation: Simple Harmonic Motion 9 answers
I don't really understand this equation and was wondering if someone could help.
The book says
when the restoring force is directly proportional to the displacement the oscillation is called SHM.
and this next part confuses me
the acceleration $a =d^2x/dt^2 = -kx/m$ so it makes sense since the second derivative of position is acc.
but how do they get that last expression?