DISCUSSION
As P moves long the rough circular arc guide, a sliding friction force acts on P, with this friction force always opposing the motion of P. You can see this in the animation above, where the friction force always point in the direction opposite to the velocity of P.
Hints:
You should follow the four-step solution plan described in the lecture book, and as discussed in lecture:
Step 1: Free body diagram (FBD) - Draw an FBD of P alone.
Step 2: Kinetics - Write down Newton's 2nd law for P. Note that the friction force on P is given by: f = μkN, where N is the normal force acting on P by the guide. You may use either the path or polar coordinates of this vector equation.
Step 3: Kinetics - Write down the polar/path components of the acceleration vector for P.
Step 4: Solve - You will have two equations and two unknowns. Solve these for the two unknowns.
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