Homework H5.B.04

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DISCUSSION and HINTS

Recall the following four-step plan outline in the lecture book and discussed in lecture:

Step 1: FBDs
Draw a single free body diagram (FBD) of the system made up of the drum, block A and the spring.

Step 2: Kinetics (work/energy)

  • Looking at your FBD above, which forces, if any, do work that is not a part of the potential energy of the system? Does the force of friction at the no-slip contact point do work? If there are none, then energy is conserved.
  • Write down the individual kinetic energy expressions for the drum and block A, and add together for the total KE of the system.
  • Define your gravitational datum line. Write down the individual potential energy expressions for the drum block A and the spring, and add together for the total PE of the system.

Step 3: Kinematics
Relate the speed of A to the angular speed of the drum.

Step 4: Solve
From your equations in Steps 2 and 3, solve for the velocity of block A at position 2.