[填空题]
An object is moving al*0ma0qxfuv456 a klce4bl, e qong a stra7ls8*jx6b rqe wu50yl ight line such that its velocity, v, $\mathrm{~ms}^{-1}$ , is given by $v(t)=5 t e^{-1.2 t}$ , for $t \geq 0 $.(two decimal places)
1. On the grid below, sketch the graph of v , for $0 \leq t \leq 3$ .
2. Find the distance travelled by the object in the first 3 seconds.
d= m
3. Find the velocity of the object when its acceleration is zero.
v(0.833)= ms$^{-1}$
