A mass of 0.2 kg is attached to the lower end of a massless spring of force constant `200 Nm^(-1)` , the upper end of which is fixed ot a rigid support . Which of the following statement is true?

Options

A. in equilibrium, the spring will be stretched by `1 cm`.
B. If the mass is raised till the spring is unstretched state and then relesed, it will go down by `2cm` before moving upwards.
C. The freuqunecy of oscillation will be nearly `5 Hz`.
D. If the system is taken to the moon, the frequency of oscillation wil be the same as on the earth.

Answer

A, B, C, D

Explanation

At equilibrium mg `= kx_(0)`
`rArr x_(0) = (mg)/(k) = ((0.2)(10))/(200) = 0.01 m = 1 cm`
Amplitude of SHM
Frequency `= 1/2pi sqrt((k)/(m)) = 1/2pi sqrt((200)/(0.2)) approx 5 Hz`.