DISCUSSION
Note that with the disk not slipping on the outer cable, and with section BC of that cable being at rest, the velocity of point C on the disk has zero velocity. This means that the disk rolls without slipping on the cable, which is the same is it were rolling without slipping on a fixed vertical wall.
With the above in mind, consider the following:
- Let M represent the point on the left side of the pulley from which the outer cable leaves contact with the disk. Note that M is moving vertically upward with a speed of vA.
- Write a rigid body kinematics equation relating the motion of points C and M: vM = vC + ω x rM/C . That equation will produce an expression for ω, the angular speed of the disk.
- Then, you can use vN = vC + ω x rN/C and vH = vC + ω x rH/C to find the velocities of point N and H on the disk. Since the inner cable does not slip on the disk, then vN = vD and vH = vQ.
- Also, vE = vC + ω x rE/C.
Any questions?? Please ask/answer questions regarding this homework problem through the "Leave a Comment" link above.