Science Homework Help

The height of a helicopter above the ground is given by h 5 3.00t 3, where H is in meters and t is in seconds.  At t 5 2.00 s, the helicopter releases a small mailbag.  How long after its release does the mailbag reach the ground?

A hard rubber ball, released at chest height, falls to the  pavement and bounces back to nearly the same height.  When it is in contact with the pavement, the lower side  of the ball is temporarily flattened. Suppose the maximum depth of the dent is on the order of 1 cm. Find  the order of magnitude of the maximum acceleration  of the ball while it is in contact with the pavement.  State your assumptions, the quantities you estimate,  and the values you estimate for them.