Q2 of 58 Page 37

A ball is gently dropped from a height of 20m. If its velocity increases uniformly at the rate of 10 ms-2 with what velocity will it strike the ground? After what time will it strike the ground?

Given : height(s) = 20m

Acceleration = 10 ms-2


To find the final velocity of ball as it reach the ground we will use 3rd equation of motion


We have, initial velocity(u) = 0 m/s


height(s) = 20m


Acceleration(a) = 10 ms-2


The third equation of motion






To find the time taken by ball the to reach the ground we will use 1st the equation of motion


We have, initial velocity(u) = 0 m/s


Final velocity(v) = 20 m/s


Acceleration(a) = 10 ms-2


1st equation of motion


v = u + at


20 = 0 + 10 t


t = = 2 s


time taken to reach the ground is 2s


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