IIT JEE , AIEEE Forum - Physics , Mechanics - A racing car moving with constant acceleration covers two succesive kilometers in 30 s . e

ganesha1991

initial velocity = U
t =30
s = 1000m
s = ut+1/2at^2
1000 = U30 + a /2 900
1000 = 30u + 450a
100=3U + 45a-----------(1)
final velocity = U + 30a

case 2
u ' = U+30a
t=20
s=1000m
1000 = (U+30a )20 + 1/2a 20*20
1000 = 20U + 600a + 200a
1000 = 20U + 800a
100 = 2U + 80a-------------(2)
(1) *2 and (2) *3
200 = 6U + 90a-----------(3)
and 300 = 6U + 240a---------(4)
(4)-(3)
100 = 150a
a = 100/150 = 2/3 =0.6666
U = 23.6

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