Disk rolling down incline problem

The video tutorial explains how to find the acceleration of the center of mass of a disk rolling down a slope. It begins with setting up the problem, including the angle of the slope and friction coefficients. The instructor uses a free body diagram to analyze forces, applies Newton's laws, and discusses torque and angular acceleration. An assumption of pure roll is tested and found incorrect, leading to the conclusion that the disk is both rolling and slipping. The final acceleration is calculated using kinetic friction.

What is the angle of the slope from the horizontal in the given problem?

• 45 degrees

• 30 degrees

• 60 degrees

• 15 degrees

Why can't the friction force be assumed to be simply mu KN for the disk?

• Because the disk is stationary

• Because the disk is a block

• Because the disk is under pure roll

• Because the disk is not on a slope

What is the direction of the normal force acting on the disk?

• Up the slope

• Perpendicular to the slope

• Down the slope

• Parallel to the slope

What is the sum of forces in the y direction equal to?

• Friction force

• mg cosine theta

• mg sine theta

• Zero

What is the moment of inertia of the disk about its center of mass?

• mr^2

• mr^2/2

• 3mr^2/2

• 2mr^2

What assumption is made about the disk's motion in the fourth section?

• The disk is sliding

• The disk is accelerating upwards

• The disk is stationary

• The disk is under pure roll

What is the maximum friction force that can occur called?

• F max

• Friction threshold

• Friction limit

• Friction peak

What does the contradiction in the pure roll assumption indicate?

• The disk is only rolling

• The disk is stationary

• The disk is only slipping

• The disk is both rolling and slipping

What type of friction is used when the disk is both rolling and slipping?

• Rolling friction

• Static friction

• No friction

• Kinetic friction

What is the final calculated acceleration of the disk's center of mass?

• 4.0554 m/s^2

• 3.0 m/s^2

• 2.5 m/s^2

• 5.0 m/s^2