Assignment:
Q1. A boat sails at a constant speed in a straight line. its position at time S is (30S- 300,10S +500). in the water there are two buoys, A and B. at positions A- (7100,2800) and B - (125700,42500).
a) Write an expression in terms of S that is the square of the distance between the boat and buoy A at time S, simplify the answer.
b) Use answer a and completing the square to find the closest distance as the boat passes buoy A (answer to nearest ten meters). what time did the closest distance occur?
c) Show that the boat passes over buoy b and tell us in minutes how long it takes to get to buoy b. assuming the boat starts at S=0.
d) What is the speed of the boat in metres per second (to 1 decimal place) and it direction as a bearing (to nearest degree).
Q2. On a second boat trip the boat starts in the same position. (-300,500) and it heading N70^oE. its speed is 30 ms ^-1 but it sails in a current of 12 ms^-1 from direction S10^o E.
Va is velocity of boat in still water.
Vw is velocity of the current
V resultant velocity of the boat.
a) Draw a diagram illustrating these three velocities as a triangle, what is the angle between Va and Vw.
b) Use the triangle and trigonometry to calculate the overall speed of the boat in m/s^-1 to 1dp. and its direction (bearing) correct to nearest degree.
(without using component form for vectors)