A man having the mass of 77 kg sits in the chair which is pin-connected to the frame BC. If the man is always seated in an upright position, determine the magitudes of the horizontal and vertical reactions of the chair on the man at the instant \theta = 45^\circ. At this instant he has a speed of 6 {\rm m/s}, which is increasing at 0.5 {\rm m/s^2}