Question

The time period of a spring pendulum with mass m is 2s. If mass is increased by 4 kg. The time period increases by one second. The initial mass m was.

Answer 1

as the time period of the spring pendulum is given by

T = 2π √m/k

now according to the question

2 = 2π√m/k

now if M = 4 + m then t = 3

3 = 2π√m + 4/k

dividing above 2 equation

2/3 = √m/m+4

squaring both sides

4/9 = m/m+4

4m + 16 = 9m

5m = 16

m = 3.2 kg is the initial mass