Final answer:
The ball will be moving at 40 m/s after 1.5 seconds, and it will have moved 48.75 meters by then when thrown downward with an initial velocity of 25 m/s from a high cliff, considering an acceleration due to gravity of 10 m/s².
Step-by-step explanation:
Understanding Free Fall and Velocity
A ball is thrown vertically downward from the edge of a high cliff with an initial velocity of 25 m/s. To determine how fast it is moving after 1.5 seconds, we use the equation of motion for objects in free fall:
v = u + gt, where v is the final velocity, u is the initial velocity, g is the acceleration due to gravity (10 m/s²), and t is the time elapsed.
(a) To find the final velocity after 1.5 s:
v = 25 m/s + (10 m/s² * 1.5 s) = 25 m/s + 15 m/s = 40 m/s.
For the distance moved, we use the formula:
s = ut + 0.5gt², where s is the displacement.
(b) To find the displacement after 1.5 s:
s = (25 m/s * 1.5 s) + 0.5 * 10 m/s² * (1.5 s)² = 37.5 m + 0.5 * 10 * 2.25 = 37.5 m + 11.25 m = 48.75 m.