Question

A ball is thrown down vertically with an initial speed of 20m/s from a height of 60 m . Find (a) its speed just before it strikes the ground ans (b) how much long it takes for the ball to reach the ground . Repeat (a)and (b) for the ball thrown directly up from the same height and with the same initial speed.​

Answer 1

Answer:

hey guys answer is option b

Answer 2

Explanation:

a..)here, u=20 m/s

s=60m

v=?

t=?

g=10m/s^2

now,

using newton's law of motion,

v^2-u^2=2gs

=v^2=2×10×60+(20)^2

v=√1200+400

v=√1600

therefore,v=40m/s... ans..

b)t=?

using newton's 1st law of motion,

v=u+at

40=20+10×t

therefore time=20/10=10sec..ans

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