Answers

2015-06-08T06:40:45+05:30
Given, s1 = 20m, v1 = 25s, s2=(160+20)m = 180m, v2 = (25+4)s = 29s
From relation v2 = u2 +2aS

So, v12 = u12 +2aS1 ...(1)
v22 = u22 +2aS2...(2)

Subtracting (1) from (2),
Agtain, u1 = u2  =0
So, v22 - v12 = 2aS2 - 2aS1
or, (180)2 - (20)2 = 2a(29-25)
or, 4000 = 8a
or, a = 500

So, velcity after 7s from rest = 0 + 500x7 m/s = 3500 m/s (Answer)
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