Question

a mass of 40 g is attached to a vertical spring it extends buy 0.4 cms find 1) force constant of the spring 2) the extension when 100 g weight is attached to it 3) the time period of oscillation of 100g weight on it 4) the time period and the force constant if the spring is cut in three equal parts and 100 gram weight is made to oscillate one part

Answer 1

use formula
F=-kX
k is spring constant

Answer 2

to find force use
f=ma
to find time period
t=1/f