50. After f seconds, a projectile hurled with initial ve- locity v and angle e will be at x(t) = v - cos(#) . t feet and y(t) = v . sin(#) - t - 1612 feet (see figure below). (This formula neglects air resistance.) (a) For an initial velocity of 80 feet/ second and an angle of ", find T > 0 so that y(T) = 0. What does this value for f represent physically? Eval- uate x(T). (b) For v and e in part (a), calculate Find T so dx that dy = 0 att = T, and evaluate x (T). What dx does x(T) represent physically? (c) What initial velocity is needed so a ball hit at an angle of $ = 0.7854 will go over a 40-foot- high fence 350 feet away? (d) What initial velocity is needed so a ball hit at an angle of 0.7 radians will go over a 40-foot- high fence 350 feet away? initial speed = v 0 = initial angle