You are asked to design a new type of loop-the-loop ride. instead of rolling down a long hill to generate the speed to go around the loop, the 310 kg cart starts at rest(with two passengers) on a track at the same level as the bottom of the 9.6 m radius loop. the cart is pressed against a compressed spring that, when released, launches the cart along the track around the loop.

part a

choose a spring of the appropriate spring constant to launch the cart so that the downward force exerted by the track on the cart as it passes the top of the loop is 0.2 times the force that earth exerts on the cart. the spring is initially compressed 6.0 m .

express your answer to two significant figures and include the appropriate units.