Three particle starts from the origin simultaneously.The firstt particle move with velocity v1 along positive x-axis. The second particle moves along positiveve y-axis with velocity v2, third particle move along the line such that y=x. What is the velocity of third particle such that all these particle lies on the same line.

Its velocity will be resultant velocity of v₁ & v₂.

      Let velocity of third particle be v.

             v = sq. root (v₁² + v₂² + cos 90)                       [angle b/w +X & +Y is 90]

            v   = sq. root (v₁² + v₂² )               Ans.

make a graph ofx,y axis and a line passing through both axis .Then locate the pts on y, x and middle of line by using using distace formula then equate the slopes of lines you will get V₃ answer will be V₃= V₁V₂root 2divded by V₁+V₂