Problem 6/110 animation

Problem No. 6/110 appears to be a relatively simple problem: the circular wheel rolls without slipping to the left. If the cm of the wheel were at the geometric center of the wheel, the wheel would roll with a constant speed, the normal force would be equal to the weight (constant) and the friction force would be zero (constant). 

However, this wheel has a "mass imbalance" with the cm G offset from the geometric center O. Watch the animation above. Note that as the wheel moves to the left,

• the speed is NOT constant. [This is due to the angular acceleration that you calculated for the wheel.]
• the normal contact force is NOT constant. [It fluctuates up/down in magnitude and is almost never equal to the weight. Can you see this in your solution? Consider how the y-component of acceleration for G varies with the position of G.]
• the friction force is NOT zero. [It fluctuates up/down in magnitude and left/right in direction. Can you see this in your solution? Consider how the x-component of acceleration for G varies with the position of G.]

Note that you are able to quantitatively predict this rather complex motion of the wheel using the Newton-Euler and kinematics. Visualizing this motion is more difficult.