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31 votes
31 votes
A ball is dropped from the roof of a 25-m-tall building. What is the velocity of the object when it touches the ground? Suppose the ball is a perfect golf ball and it bounces such that the ve locity as it leaves the ground has the same magnitude but the op posite direction as the velocity with which it reached the ground How high will the ball bounce? Now suppose instead that the ball bounces back to a height of 20 m. What was the velocity with which it left the ground?

User PeeteKeesel
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1 Answer

21 votes
21 votes

Answer:

a)
h=25m

b)
v=19.8m/sec

Step-by-step explanation:

From the question we are told that:

Height
h=25m

Bounce Height
h'=20m

Generally the Kinematic equation is mathematically given by


V=√(2gh)\\\\V=√(2*9.81*25)


V=22.1m/sec

Therefore Height


h=(V^2)/(2g)\\\\h=(22.1^2)/(2*9.81)


h=25m

b)

Generally the Kinematic equation is mathematically given by


v^2=2ah


v^2=2*9.8*20


v=√(2*9.8*20)


v=19.8m/sec

User Lex Carter
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2.8k points