multiple choice

The figure shows scale drawings of four objects, each of the same mass and uniform thickness, with the mass distributed uniformly. Which one has the
greatest moment of inertia when rotated about an axis perpendicular to the plane of the drawing at point P?

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Rotational Kinetic Energy: Consider a uniform hoop of radius R and mass M rolling C

without slipping. Which is larger, its translational kinetic energy or its rotational kinetic

energy?

• Rotational kinetic energy is larger
  

• Translational kinetic energy is larger.
  

• Both are equal.

• You need to know the speed of the hoop to tell.

1. Consider a solid uniform sphere of radius R and mass M rolling without slipping. Which form of its kinetic energy is larger, translational or rotational?

• 0. Rotational kinetic energy is larger.
     

• 0. Translational kinetic energy is larger.

• 0. Both are equal.
     

• 0. You need to know the speed of the sphere to tell.

1. A solid sphere and a solid cylinder, both uniform and of the same mass and radius, roll without slipping at the same forward speed. It is correct to
   say that the total kinetic energy of the solid sphere is

• 0. less than the total kinetic energy of the cylinder.

• 0. more than the total kinetic energy of the cylinder.

• 0. equal to the total kinetic energy of the cylinder. 1

5. A disk and a hoop of the same mass and radius are released at the same time at the top of an inclined plane. If both are uniform, which one reaches
   the bottom of the incline first if there is no slipping?

• 0. The disk

• 0. The hoop

• 0. Both reach the bottom at the same time.

5. Two forces produce equal torques on a door about the door hinge. The first force is applied at the midpoint of the door; the second force is applied at the doorknob.
   Both forces are applied perpendicular to the door. Which force has a greater magnitude?

• 0. the second force (at the doorknob)

• 0. the first force (at the midpoint)

• 0. The two forces are equal.

5. Two equal-magnitude forces are applied to a door at the doorknob. The first force is applied perpendicular to the door, and the second force is applied at 30° to the
   plane of the door. Which force exerts the greater torque about the door hinge?

• 0. the second force (applied at an angle)
     

• 0. the first force (applied perpendicular to the door)

• 0. Both forces exert equal non-zero torques.

• 0. Both forces exert zero torque.

5. As shown in the figure, a given force is applied to a rod in several different ways. In which case is the torque about the pivot P due to this force the greatest?

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9. Five forces act on a rod that is free to pivot at point P, as shown in the figure. Which of these forces is producing a counter-clockwise torque about point P? (There
   could be more than one correct choice.)

• A

• B

• C

• D

• E

9. The rotating systems shown in the figure differ only in that the two identical movable masses are positioned a distance r from the axis of rotation (left),
   or a distance r/2 from the axis of rotation (right). If you release the hanging blocks simultaneously from rest,

• 0. the block at the left lands first.

• 0. the block at the right lands first.

• 0. both blocks land at the same time.