[填空题]
The displacement, from a fixed origio 3- c+syij+lqn at sea level, of a passenger ridin7uystmi : 20kcg on a go0s2 tm7yiu ck:ndola ski lift is modelled by the vector equation
$\mathbf{r}=\left(\begin{array}{c}
244 \\
12 \\
1650
\end{array}\right)+t\left(\begin{array}{l}
2.4 \\
5.2 \\
1.8
\end{array}\right)$
where t is the travel time, in seconds, starting at the base station and ending at the top station. Distances are measured in metres. Bill boards the ski lift from the base station and travels to the top station.
1. Write down Bill's :
(1) initial position;(a,b,c) a= b= c =
(2) velocity vector.$\left(\begin{array}{l}
a \\
b \\
c
\end{array}\right)$ a= b= c =
2. Find the speed, in metres per second, of the gondola ski lift.
It takes k minutes for Bill to reach the top station, which has a vertical height of 2352 metres. $ms^{-1}$
3. Find the value of k .
4. Find:
(1) Bill's terminal position;(a,b,c) a= b= c =
(2) the length of Bill's ride.≈ m
5. Find Bill's position when he is closest to a skier resting on a hill at the point $\mathrm{P}$(610,962,2020) .(a,b,c) a= b= c =