Answer Happy

3. The small blocks A and B are connected by a straight rod, and the entire system is rotating counter-clockwise in the horizontal x-y plane about O with angular speed . When the rod aligns with the x-axis, the link between A and B is cut (see drawing). After link AB is cut, block A continues to rotate around O, while Block B moves in a straight line in the y- direction. mA = 6 kg, mB = 3 kg, loA = 3 m, lAB = 1 m. The rod has zero mass. 5 (a) Let = 3.5 radians/second. What is total angular momentum of the system about point O before link AB is cut? 10 (b) After link AB is cut, the bar OA (with block A still attached) continues to rotate about point O, with initially equal to 3.5 radians/second. A moment M = Kė is then applied to OA to slow it down and finally stop it rotating about point O within exactly 5 seconds. Find the constant K. 10 (c) After link AB is cut, block B comes in contact with the wall for t= 0.2 sec, and changes direction. If = 5.4ĵ m/s before B hits the wall, and vg'= 4.2î m/s after B hits the wall, find the average force F applied by the wall on B during the time of contact. 25 marks for question #3 AY wall VB loA Page 3 of four pages LAB B B