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Question
A ball is thrown upward and reaches a maximum height of 19.6 m. Find its initial speed?
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Solution
Maximum Height attained by ball = 19.6 m
Let initial speed of ball = u ms-1.
Acceleration applied on ball due to gravity = -9.8 ms-2.
Final speed of ball at maximum height = 0 ms-1.
We know that from second equation of motion
V2 - u2 = 2as
0 -u2 = 2 X(-9.8)X19.6
u2 = 19.6 X 19.6
u= 19.6 ms-1
So initial speed of ball to attain maximum height of 19.6 m should be 19.6ms-1.
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