A 1 m diameter sphere is droped from an evacuated 145 m drop tower.
1) how long is sphere in free fall ??
2) when it reaches bottom, it experiences an avg decceleration of 25 g . Through wat dist it travel during decceleration ??

Dear Mohit,

s = ut + 1/2 at² (where a = g)
145 = 0 + 1/2 10 t²
t = sqrt(29) s

Second question is a bit shady. From average decceleration one can't calculate the distance, only change in velocity. More precisely it should have mentioned "CONSTANT" decceleration. Then

v2 = u2 + 2as will give you the answer where u = at = 10*sqrt(29) and v = 0.


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