Question 3 (a) The loaded 150 kg skip is rolling down the incline at 4 m/s when a force P is applied at time 1-0 to the cable as shown in Figure Q3a. The force P increased uniformly with the time until it reaches 600 N at 1-4s, after which it remains constant at this value. (i) Draw the free body diagram of the skip. (ii) (iii) Determine the time at which the skip reversed its direction. Determine the velocity of the skip at 8s. (3 marks) (9 marks) (3 marks) (b) Up = 4 m/s 30 Figure Q3a A hollow cylindrical block of weight 100 N is attached by two springs, one on each side, and is allow to move freely along a vertical rod as shown in Figure Q3b. If the stiffness of both the springs is 800 N/m and the unstretched length is 0.3 m, determine the total elastic energy of the spring at point A, determine the velocity of the cylindrical block at point B if it drops from (2 marks) (i) (ii) point A, (4 marks) (iii) if an external force of 10 N (downward) is now applied on the cylindrical block, calculate the new velocity of the block as it passes B. (4 marks) 0.4 m 0.4 m B 0.3 m Figure Q3b