Consider a uniform solid disk of mass M and radius R rolling without slipping down an incline at ang ...

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Consider a uniform solid disk of mass M and radius R rolling without slipping down an incline at angle gamma to the horizontal. The instantaneous point of contact between the disk and the incline is called P. (a) Draw a free-body diagram showing all forces on the disk. (b) Find the linear acceleration of the disk by applying dL/dt = Gamma_ext for rotation about P. (Remember to use the parallel-axis theorem for rotation about a point on the circumference.) (c) Derive the same result by applying dL/dt = Gamma_ext to the rotation about the center of mass. (In this case there will be an extra unknown, the force of friction, which you can eliminate using the equation of motion of the center of mass.)