24. A 78 g steel ball is released from rest and falls vertically onto a rigid surface. The ball strikes the surface and is in contact with it for 0.5 ms. The ball rebounds elastically, and returns to its original height
during a round trip of 4 s. Assume that the surface does not deform during contact. What is the
maximum elastic energy stored by the ball? (Use acceleration due to gravity g = 10 m/s2)
A. 23.1)
B. 43)
C. 11.5 J
D. 15.6)

You have been hired to design a spring-launched roller coaster thatwill carry two passengers per car. the car goes up a 10-m highhill, then descends 15m to the track's lowest point. you'vedetermined that the spring can be compressed a maximum o 2.0m andthat a loaded car will have a maximum mass of 400kg. for safetyreasons, the spring constant should be 10% larger than the minimumneeded for the car to just make it over the top. a) what spring constant (k) should you specify ? b) what is the maximum speed of a 350 kg car if the spring iscompressed the full amount.