Question

Initial velocity of A and B are 5m/sec and 1m/sec. They move with consant acceleration of 6m/sec2 and 2 m/sec2. Distance between A and B is 16m. After how much time A and B are together
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Answer 1

Explanation:

Relative initial velocity of A wrt B = v(AB) = v(A)-v(B) = 5-1 = 4m/sec

Relative acceleration of A wrt B = a(AB) =a(A)-a(B) =6-2=4m/sec²

distance between A and B = 16m

Let both A and B are together after time t second

then during that time A travel 16m more than B

then s = 16m

applying the equation s = ut + ½at² and substituting the proper values we obtain

16 = 4t + ½×4×t²

2t²+4t-16=0

solving this equation we get

t=2 second or t= -4 second