(a) Both spheres are launched with 0 initial velocity in the vertical direction, so they both hit the ground at time t such that
10 m - 1/2 g t ² = 0
where g = 9.80 m/s² is the magnitude of the acceleration due to gravity.
Solve for t :
10 m = 1/2 g t ²
t ² = (20 m) / g
t ≈ 1.4 s
(b) Sphere A travels a horizontal distance of
(5.0 m/s) (1.4 s) ≈ 7.1 m
while sphere B travels a distance of
(2.5 m/s) (1.4 s) ≈ 3.6 m
