Question 1
[ In this question i and j are horizontal unit vectors due east and due north respectively and position vectors are given relative to a fixed origin O.] Two cars P and Q are moving on straight horizontal roads with constant velocities. The velocity of P is (15i + 20j) m s–1 and the velocity of Q is (20i – 5j) m s–1
Find the direction of motion of Q, giving your answer as a bearing to the nearest degree.
(3)
At time t = 0, the position vector of P is 400 i metres and the position vector of Q is 800 j metres. At time t seconds, the position vectors of P and Q are p metres and q metres respectively.
Find an expression for
p in terms of t,
q in terms of t.
(3)
Find the position vector of Q when Q is due west of P.
(4)