Please help me in finding answer for the following as early as possible as my test on the same is in two days time. I am totally confused. 
A particle P is moving with constant velocity (-5i+8j) m/s. Find
a) the speed of P
b) the direction of motion of P, giving your answer as a bearing
At time t=0, P is at the point with position vector (7i-10j) m relative to a fixed origin O. When t=3 s, the velocity of P changes and it moves with velocity (ui+vj) m/s, where u and v are constants. After a further 4 s, it passes through O and continues to move with velocity (ui+vj) m/s.
c) Find the values of u and v.
d) Find the total time taken for P to move from A to a position which is due south of A.
A particle P is moving with constant velocity (-5i+8j) m/s. Find
a) the speed of P
b) the direction of motion of P, giving your answer as a bearing
At time t=0, P is at the point with position vector (7i-10j) m relative to a fixed origin O. When t=3 s, the velocity of P changes and it moves with velocity (ui+vj) m/s, where u and v are constants. After a further 4 s, it passes through O and continues to move with velocity (ui+vj) m/s.
c) Find the values of u and v.
d) Find the total time taken for P to move from A to a position which is due south of A.
