49. You have been hired to design a spring launched roller coaster that will carry two passengers per car. Te car goes up a 10m high hill, then descends 15m to the track's lowest point. You've determined that the spring can be compressed a maximum of 2.0 m and that a loaded car will have a maximum mass of 400 kg. For safety reasons, the spring constant should be 10% larger than the minimum needed for the car to just make it over the top. a. What spring constant should you specify? b. What is the maximum speed of a 350 kg car if the spring is compressed the full amount? I'm having trouble with part a. Here's what I've got so far: known: m=400kg y0= 5m y1= 15m y2= 0m v1= 0 m/s s0= -2.0m (compression of spring) s1= 0m to find: k v0 .5mv0^2+mgy0+.5kS0^2 = .5mv1^2+mgy1+.5kS1^2 200v0^2+19600-2k = 58800 am I on the right track? how do I find out what I need to get to solve for part a of the problem?