1. An average force of 8.2 newtons is used to pull a .4 kg rock, stretching a sling shot 43 centimeters. The rock is shot downward from a bridge 18 meters above a stream. What will be the velocity of the rock just before it hits the water? How much time will it take to hit the water. 2. Relevant equations 3. I just want to know if the spring/work equation, .5k(x)squared=w applies to the slingshot, and would stretching it by 43 CM = the x part of the equation? I don't know what to do once I get work. How do i get the velocity of the rock? I know A after shot would be 9.8, d is 18, but is final Velocity 0?