Two cannons sit on top of a 100 m high cliff. they fire identical cannon balls at the exact same moment. cannon ball a is fired at 20 m/s. cannon ball b is fired at 15 m/s. what will cannon ball b's vertical velocity (vx) be after 3 seconds?

This is kenetic energy.

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.