There is a device which entertains infants while keeping them from wandering. The child bounces in a harness suspended from a door frame by a spring.

If the spring stretches 0.200 m while supporting a 7.2 kg child, what is its force constant (in N/m)?

What is the time (in s) for one complete bounce of this child?

What is the child's maximum speed (in m/s) if the amplitude of her bounce is 0.190 m?