In the arrangement shown in figure the ends P and Q of an unstretchable string move downwards with uniform speed U pulley A and B are fixed . Mass M move upwards with a speed.
(A) 2Ucosθ                          (B) U/cosθ           (C) 2U/cosθ                      (D) Ucosθ      
Physics Pully Based question of IIT
A Particle is moving eastward with a velocity of 5m/s. In 10 s the velocity changes to 5 m/s northwards. what is the average acceleration in this time ?