One of the greatest difficulties with setting up the baby bouncer is determining the right height above the floor so that the child can push off and bounce. Knowledge of physics can be really helpful here. If the spring constant (k=5.0 x 10^2 N/m) , the baby has a mass (m=11kg) , and the baby's legs reach a distance (d=0.15m) from the bouncer, what should be the height (h)of the "empty" bouncer above the floor?

0.365 m.

Explanation:

When the baby steps on the bouncer without bouncing, the equilibrium length will be determined using the fact that the net force on the equilibrium is equal to zero.

If the equilibrium length of the bouncer is 0.215 m, and the maximum distance the baby jumps from this distance is 0.15 m, then the baby will sink the same distance to the ground from the equilibrium length of the bouncer.

So, If the empty length will be adjusted as 0.215 + 0.15 = 0.365 m, then the baby will not hit the ground.

the bal will not change its velocity.