The radius vector of a particle varies with time t as `vecr=vecbt(1-alphat)` is a constant vector and a is a positive factor.Find the time interval `Deltat` taken by the particle to return to the initial point.

Explanation

`vecr=vecbt(1-alphat)`
For initial point ,`vecr=0,vecb=t(1-alphat)=0`
t=0 and `t=(1)/(alpha)` Hence, `Deltat=(1)/(alpha)`