A particle is moving such that its position vector varies with time as vec(r) = (1 - alpha t) t vec(A) , where alpha and vec(A) are constant quantities. At t = 0, the particle is at a position O. At some later instant 't_(0)', the particle is again at O. Velocity of the particle at the instant t_(0) is:

A particle is moving such that its position vector varies with time as

1.	A particle is moving such that its position vector varies with time as vec(r) = (1 - alpha t) t vec(A) , where alpha and vec(A) are constant quantities. At t = 0, the particle is at a position O. At some later instant 't_(0)', the particle is again at O. Velocity of the particle at the instant t_(0) is:
Answer» `2 vec(A)` `vec(A)` `-vec(A)` `-2 vec(A)` Solution :`vec(R) = (1 - alpha t)t vec(A)` `(d vec(r))/(DT) = (1- 2 alpha t) vec(A)`