An incredibly large slingshot is stretched 1.5 meters to launch a 180.0-gram projectile with a speed sufficient to escape from the Earth (11.2 km/s). Assume the elastic sling obeys Hooke's law. What is the spring constant of the device if all the potential energy is converted to kinetic energy? 1.004×107 N/m is the answer to the first part. Need help with the second part below. Assume that the average person can exert a force of 220 Newtons. How many people would be required to stretch the slingshot?