total energy (E) of a projectile is the sum of its kinetic and potential energy: E= 1/2 mV^2 +mgz where m is mass of projectile, V is speed, g is gravitational constant and z is height. 5.0 kg object, dropped from rest (V=0 at time t=0) what will speed of the object be in m/s after it has fallen 10 ft. gravitational constant 32 ft/s^2