A force F is given by F = (10i + j)N.
(a) Find the exact value of the magnitude of F.
(b) Find, in degrees, the size of the angle between the direction of F and the direction of
the vector (i + j).
The resultant of the force F and the force (–15i + aj)N, where a is a constant, is parallel
to, but in the opposite direction to, the vector (2i – 3j).
(c) Find the value of a.