Two boys are standing at the ends A and B of a ground, where `AB=a`. The boy at B starts running in a direction perpendicular to AB with velocity `v_(1)`. The boy at A starts running simultaneously with velocity v and catches the other boy in a time t, where t is :

Explanation

Let the boy at (A) catches the boy (B) at point (c ) aftre time (t), Fig. 2 9b) .24.
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Here, ` AC =vt, BC =v_(1) t`
As `AC^(2)=a^(2) + (v_(1) t)^(2)`
:. `(vt) ^(2) =a^(2) + (v_(1) t)^(2)`
or `t^(2) (v^(2)-v_(1)^(2) =a^(2) or =a/(sqrt v^(2) -v_(1)^(2)`.