Consider the situation depicted above, in which a purple block is

released from rest on a frictionless track. After sliding down the first

portion of the track, the block encounters a circular bump in the track of

radius r = 15 meters. If the block moves over the bump too fast, it will

leave the track and launch into the air. What is the greatest height, h,

from which the block can be released and still make it over the bump

without leaving the track? Express your answer in meters.