an object is thrown off a cliff with intial pward velocity of 15m/s it strikes the ground with downward velocity of 25 m/s what is the height of the cliff

20 m

Explanation:

Given:

v₀ = 15 m/s

v = -25 m/s

a = -10 m/s²

Find: Δy

v² = v₀² + 2aΔy

(-25 m/s)² = (15 m/s)² + 2 (-10 m/s²) Δy

Δy = 20 m

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.