Ask and answer questions here. You learn both ways.
DISCUSSION and HINTS
Shown below is an animation of the motion for particle P as it moves around on its circular path. Note that the normal force acting on P switches from contact on the outer surface (normal force pointing inward) to contact on the inner surface (normal force pointing outward) and back to contact on the outer surface. Also note that the friction force always opposes the sliding motion of P, as should be expected. (Note that the parameters used in the simulation producing this animation may differ from the ones used in this semester’s homework set.)
Recall the following four-step plan outline in the lecture book and discussed in lecture:
Step 1: FBDs
Draw a free body diagrams for P. Be sure to show the friction force opposing the motion of P in your FBD.
Step 2: Kinetics (Newton’s 2nd Law)
Using a set of path unit vectors for resolving forces into components is recommended here. Write down the appropriate Newton’s 2nd law equation in normal and tangential directions. Recall that f = μk*|N|.
Step 3: Kinematics
Since you have used a path description for resolving forces, you should also use a path description for acceleration; that is, aP = v_dot et +(v2/r) en.
Step 4: Solve
At this point you will have two equations in terms of two unknowns: N and v_dot.