The position of a particle is given by `barr=(3.0thati-2.0t^2hatj+4.0hatk)`m where 't' is in seconds. (a) Find `barv` and `bara` of the particle (b) What is the magnitude and direction of velocity of the particle at t=0.0s ?

Explanation

Given `vecr=3.0thati-2.0t^2hatj+4.0hatk`
where `vecv=(dvecr)/(dt)=3.0hati-2.0thatj" at "t=2.0s,vecv=3.0hati-4.0hatj`
so that `|vecv|=sqrt(3^2+4^)=5m//s" "veca=(dvecv)/(dt)=-2hatj`
and `|veca|=a=2ms^(-2)`