Problem statementSolution video |

**DISCUSSION THREAD**

**Discussion and hints:**

The constant applied force *F* acts only in the x-direction. Therefore, as explained in the lecture book, the work done by *F* is simply the force multiplied by the distance traveled by particle A in the *x*-direction. Use this result in the Step 2 of your analysis.

Recall the following *f**our-step plan* outline in the lecture book and discussed in lecture:

**Step 1: FBD**

Draw a free body diagram of the system made up of A+B+bar. Which, if any, forces do non-conservative work on this system? Can you justify this from the FBD?

**Step 2: Kinetics (work/energy equation)**

Write down the work energy equation for the system. The KE for the system is the sum of that for A and B. The PE for the system is the sum of that for A and B. Consider the above discussion when calculating the work done by the force *F*.

**Step 3: Kinematics**

What is the horizontal distance traveled by B? How are the speeds of A and B related to the angular speed of the bar?

**Step 4: Solve**

Solve your work/energy equation for the angular speed of the bar.

Any questions??

The only work in this problem is done by F, correct?

Right, all other work done on the system (gravity) is conservative, so you account for it with the change in potential energy

Do we consider the distance F moves point B or just point A?