A ball is thrown upward at an angle with a speed and direction such that it reaches a maximum height of 16.0 m above the point it was released, with no appreciable air resistance. At its maximum height it has a speed of 18.0 m/s. With what speed was the ball released?
A) 25.3 m/s
B) 22.2 m/s
C) 33.0 m/s
D) 29.2 m/s
E) 36.9 m/s

Question

Quizplus · Accepted Answer

At maximum height, the vertical component of velocity is zero. So,$$v_{yf}^2 = v_{yi}^2 + 2g(y_f - y_i)$$$$0 = v_{yi}^2 - 2(9.8)(16)$$$$v_{yi} = 29.2 \ m/s$$The speed at release is:$$v_i = \sqrt{v_{xi}^2 + v_{yi}^2}$$$$v_i = \sqrt{(18)^2 + (29.2)^2} = 33.0 \ m/s$$

A Ball Is Thrown Upward at an Angle with a Speed