The velocity vector in the flow field is given by: $(15\%)$

$u=\frac{x}{1+t},v=\frac{2y}{1+t},w=\frac{3z}{1+t}$

$($a$)$ Find the acceleration of this flow field in the Eulerian system.

$($b$)$ Find the acceleration of this flow field in the Lagrangian system for a particle released at the point $(x_0,y_0,z_0)$ at time $t=0.($Hint: find the streakline first$)$

$($c$)$ Find the expression of the streamline.