Question

A child is in a bouncy swing suspended from a spring. If the spring stretches 15cm when

the8.5 kg child is put in it, what is its spring constant? How much time does it take for the

child to complete one bounce?

Answer 1

Apply Hooke's law:

$$k=mg/x=555\text{ N/m}.$$

Now, find the period of oscillation:

$$T=2π\sqrt{m/k}=0.78\text{ s}.$$