Question

A boy drops a ball from a cliff of 122.5 m high. Find:
How long does it take the ball to fall to the ground?
ii) How far does it fall in the first three seconds?
(iii) How fast is it going at the end of three seconds?
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Answer 1

(1)s=ut+1/2gt^2

therefore

122.5=0×t+1/2×9.8×t^2

122.5/4.9=t^2

therefore, t^2=25

t=5s.

(2)s=ut+1/2gt^2

therefore,

s=0×t+4.9×9

therefore,

s=44.1m

(3)v=u+gt

therefore,

v=o+9.8×3

v=29.4 m/s.