An incredibly large slingshot is stretched 1.0 meters to launch a 128.0-gram projectile with a speed sufficient to escape from the Earth (11.2 km/s). Assume the elastic sling obeys Hooke's law.
a) What is the spring constant of the device if all the potential energy is converted to kinetic energy?
b) Assume that the average person can exert a force of 220 Newtons. How many people would be required to stretch the slingshot?