b) Adam walks in a straight line form the point A(-1, 4) to the point Q(4, 16) with constant speed. His position vector can be expressed in the form p = a + tu, where t is the time after he starts walking. Adam arrives at the point Q at t = 3. ~ A (-1,4) i. State the vectors a and u. y Q(4,16) B (11,9) ii. Bob is at point B(11,9). During Adam's walk from A to P, Bob wishes to throw a ball to Adam. Bob decides to throw the ball when Adam is at the closest point to B. a) Write a vector w that is perpendicular to u. B) Hence or otherwise, find value of t when Bob throws the ball to Adam.