Question

A particle is thrown vertically upward. It is known that the distance traveled in 6th second and 7th second is the same then:

(a) The particle was thrown with 40 m/s
(b) The particle was thrown with 70 m/s
(c) Total vertical height is 245 m
(d) Total vertical height is 180 m

*No guesses please, give detailed explanation.

Answer 1

diatance travelled can be same only if the particle has reached its max height at the end of 6 sec. so Max height =0.5*g*t^2 = 0.5*10*36 = 180 m
the initial velocity required is sqrt(2gH) = sqrt(2*10*180)= 60 mps

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