Question
Thu June 09, 2011 By: Pooja Dev

a particle moves from a point (5,-1,4)to (-1,-9,4)if the speed of the particle is 25m/s, then what is the velocity vector of the particle ? 1)2i^+1.5j^ 2)-1.5i^+2j^ 3)(2i^+1.5j^)/25 4)(-1.5i^-2j^)/25 choose the right answer .

Expert Reply
Mon June 13, 2011
The displacement vector of the particle = (-1-5)i^ + (-9+1)j^ + (4-4)k^ = -6i^ - 8j^
 
The direction in which the particle is moving = (-6i^ - 8j^)/sqrt (36+64) = (-6i^ - 8j^)/10
 
Thus the velocity vector = (-0.6i^ - 0.8j^)x 25 = -15i^ - 20j^
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