A ball is thrown horizontally from the top of a building 30.1 m high. The ball strikes the ground at a point 66.8 m from the base of the building.

Question

The acceleration of gravity is 9.8 m/s2 . Find the time the ball is in motion. Answer in units of s

Find the initial velocity of the ball. Answer in units of m/s

Find the x component of its velocity just be- fore it strikes the ground.
Answer in units of m/s

Find the y component of its velocity just be- fore it strikes the ground.
Answer in units of m/s

Someone please explain! Thank you

Answer 1

h = 30.1 m.
Dx = 66.8 m.

1. h = Yo*t + 0.5g*t^2 = 30.1
0 + 4.9t^2 = 30.1
t^2 = 6.143
Tf = 2.48 s. = Fall time or time in motion.

2. Dx = Xo*Tf = 66.8
Xo * 2.48 = 66.8
Xo = 27 m/s. = Initial velocity.

3. X = Xo = 27 m/s = X component of velocity just before it hits gnd.

4. Y^2 = Yo^2 + 2g*h = 0 + 19.6*30.1 =
590
Y = 24.3 m/s. = Y component of its' velocity just before it hits gnd.