A ball is thrown horizontally from the top of a 20-m high hill. It strikes the ground at an angle of 45o45o . With what speed was it thrown?

V = 19.79 m/s

Explanation:

given,

height of the hill, h = 20 m

angle of strike,θ = 45°

Speed of thrown = ?

using equation of motion for time calculation

  t = 2.02 s

Horizontal velocity = v_x = V

Vertical velocity = v_y= g t

                              v_y = 9.8 x 2.02 = 19.79 m/s

now, we know,

  V = 19.79 m/s

Hence, the speed at which ball was thrown is equal to 19.79 m/s.

hey , the answer is c