Question

A mass M is attached to an ideal massless spring. When this system is set in motion with amplitude A, it has a period T. What is the period if the amplitude of the motion is increased to 2A
1 : 2T
2 : T/2
3 : T
4 : 4T

Answer 1

$T=2\pi \sqrt\frac{m}{k}$

Increase of Amplitude by $2A$ the period does not change. Therefore the period remain T.

Answer 3. T