BC=√[40? +(8√3)? ]= 16√7
Ship speed =16 √ 7/(4/3) =12 √ 7 km/h.
(2) In the coordinate system as shown in the figure.
B(-20,20√3)C( 12,4√3)
Let a straight line lbc: y = kx+b.
Substitute the coordinates of b and c into y = kx+b.
Get -20k+b=20√3。
12k+b=4√3
The solution is k =-3/2 b =10 √ 3.
∴ Linear LBCY =-3/2x+10 √ 3
When y=0, x=20 is E (20,0).
∫M( 19.5,0),N(20.5,0)
If the ship continues to sail and does not change its course, it can directly dock in MN.