Chapter 6.5, Problem 121PE

For Exercises 120-121, consider a projectile launched from ground level at an angle of elevation $\theta$ with an initial velocity $v_0.$ The maximum horizontal range is given by $x_{\max }=\frac{v_0{}^2\sin 2\theta }{g},$ where g is the acceleration due to gravity $\left(g=32{\text{ft/sec}}^{\text{2}}\text{or }g=9.8{\text{m/sec}}^{\text{2}}\right).$

121. A quarterback throws a football with an initial velocity of 62 ft/sec to a receiver 40 yd (120 ft) down the field. At what angle could the ball be released so that it hits the receiver's hands at the same height that it left the quarterback's hand? Round to the nearest tenth of a degree.