Answer:
k = 3.5 N/m
Explanation:
It is given that the time period the bob in pendulum is the same as its time period in spring mass system:
[tex]Time\ Period\ of\ Pendulum = Time\ Period\ of\ Spring-Mass\ System\\2\pi \sqrt{\frac{l}{g}} = 2\pi \sqrt{\frac{m}{k}[/tex]
[tex]\frac{l}{g} = \frac{m}{k}\\\\ k = g\frac{m}{l}[/tex]
where,
k = spring constant = ?
g = acceleration due to gravity = 9.81 m/s²
m = mass of bob = 125 g = 0.125 kg
l = length of pendulum = 35 cm = 0.35 m
Therefore,
[tex]k = (9.81\ m/s^2)(\frac{0.125\ kg}{0.35\ m})\\\\[/tex]
k = 3.5 N/m