A 58.0-kg projectile is fired at an angle of 30.0° above the horizontal with an initial speed of 1.38 102 m/s from the top of a cliff 156 m above level ground, where the ground is taken to be y = 0.
(a) What is the initial total mechanical energy of the projectile?
J
(b) Suppose the projectile is traveling 97.8 m/s at its maximum height of y = 354 m. How much work has been done on the projectile by air friction?
J
(c) What is the speed of the projectile immediately before it hits the ground if air friction does one and a half times as much work on the projectile when it is going down as it did when it was going up?
m/s