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Question
An object falling freely from rest reaches ground in 2 s. If acceleration due to gravity is 9.8 m s-2, then the velocity of object on reaching the ground will be
Options
9.8 m s-1
4.9 m s-1
19.6 m s-1
Zero
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Solution
An object falling freely from rest reaches ground in 2 s. If acceleration due to gravity is 9.8 m s-2, then the velocity of object on reaching the ground will be 19.6 m s-1
METHOD: Given, u = 0
g = 9.8 m/s2
Time t = 2s
Let 'v' be the velocity of object on reaching the ground.
Using the first equation of motion,
v = u + gt
We get,
v = 0 + (9.8) (2)
Or, v = 19.6 m/s.
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