The position of a particle is given by ` vec r= 3.0 t hat i - 2.0 t^2 hat j + 4.0 hat k m`, wher (t) in seconds and the coefficients have the proper units for ` vec r` to be in metres. (a) Fing the ` vec v` and ` vec a` of the particle ? (b) What is the magnitude and direction fo velocity of the particle at ` t= 2 s`?

Answer

(a) `v(t)=(3.0 hat(i)-4.0 hat(j)) hat(a) (t)=-4.0 hat(j)` (b) `8.54 ms^(-1). 70^(@)` with x-axis