A particle P is projected vertically upwards from a point on the ground with speed 17 m s^-1. Another particle Q is projected vertically upwards from the same point with speed 7 m s^-1. Particle Q is projected T seconds later than particle P.

1. Given that the particles reach the ground at the same instant, find the value of T.
2. At a certain instant when both P and Q are in motion, P is 5 m higher than Q. Find the magnitude and direction of the velocity of each of the particles at this instant.