11 st one i am getting c
Q1.A boy is standing in an elevator accelerating upward throws a ball upward with a velocity v.The ball returns in his hands after a time t.The acceleration of the lift is -
(a)2v-gt/t
(b)2v+gt/t
(c)v-gt/t
(d)v+gt/t
Q2.Two identical balls upwards one after the another at an interval of 2s along the same vertical line with the same initial velocity of 40m/s.The height at which the balls collide are -
(a)50m
(b)75m
(c)100m
(d)125m
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UP 0 DOWN 0 0 8
8 Answers
6ans for Q1 is (a) and Q2 is (b).....
Plz explain how u got the answer.
1when the 1st ball reaches the highest pointie,,80m 2nd ball is at 60m.rel. dist.=20m, relative acceration=20 init. vel. of 1st ball =0.init. vel. of 2nd ball=20m/s.
equating, 10t^2=20t-10t^2
t=1. in 1 sec., 1st bal. travels 5m down.
H=75