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Two wheels initially at rest roll the same distancewithout slipping down identical inclinedplanes starting from rest. Wheel B hastwice the radius but the same mass as wheelA. All the mass is concentrated in their rims,so that the rotational inertias are I = mR2.Which has more translational kinetic energywhen it gets to the bottom?

1. Wheel A2. Wheel B3. The kinetic energies are the same.4. need more information

A ladybug sits at the outer edge of a merry-go-round, and a gentleman bug sits halfwaybetween her and the axis of rotation. Themerry-go-round makes a complete revolutiononce each second. The gentleman bug’sangular speed is

1. half the ladybug’s.2. the same as the ladybug’s.3. twice the ladybug’s.4. impossible to determine

A ladybug sits at the outer edge of a merry-go-round, that is turning and slowing down.At the instant shown in the figure, the radialcomponent of the ladybug’s (Cartesian)acceleration is

1. in the +x direction.2. in the –x direction.3. in the +y direction.4. in the –y direction.

A ladybug sits at the outer edge of a merry-go-round, that is turning and slowing down.At the instant shown in the figure, the radialcomponent of the ladybug’s (Cartesian)acceleration is

1. in the +x direction.2. in the –x direction.3. in the +y direction.4. in the –y direction.

A ladybug sits at the outer edge of a merry-go-round that is turning and is slowing down.The vector expressing her angular velocity is

1. in the +x direction.2. in the –x direction.3. in the +y direction.4. in the –y direction.5. in the +z direction.6. in the –z direction.

Consider two people on opposite sides of arotating merry-go-round. One of them throwsa ball toward the other. In which frame of ref-erence is the path of the ball straight whenviewed from above: (a) the frame of themerry-go-round or (b) that of Earth?1. (a) only2. (a) and (b)—although the paths appearto curve3. (b) only4. neither; because it’s thrown while in circularmotion, the ball travels along acurved path.

You are using a wrench and trying to loosena rusty nut. Which of the arrangementsshown is most effective in loosening the nut?List in order of descending efficiency the following arrangements:a)1, 3, 4, 2b)2, 4, 1, 3c)4=2, 1, 3d)4=2, 1=3e)2, 1=4, 3

A force F is applied to a dumbbell for a timeinterval Δt, first as in (a) and then as in (b). Inwhich case does the dumbbell acquire thegreater center-of-mass speed?

1. (a)2. (b)3. no difference4. The answer depends on the rotationalinertia of the dumbbell.

Aforce F is applied to a dumbbell for a timeinterval Δt, first as in (a) and then as in (b). Inwhich case does the dumbbell acquire thegreater energy?

1. (a)2. (b)3. no difference4. The answer depends on the rotationalinertia of the dumbbell.

Imagine hitting a dumbbell with an objectcoming in at speed v, first at the center, thenat one end. Is the center-of-mass speed ofthe dumbbell the same in both cases?1. yes2. no

A box, with its center-of-mass off-center as indicatedby the dot, is placed on an inclinedplane. In which of the four orientations shown,if any, does the box tip over?

Consider the situation shown at left below.A puck of mass m, moving at speed v hits anidentical puck which is fastened to a poleusing a string of length r. After the collision,the puck attached to the string revolvesaround the pole. Suppose we now lengthenthe string by a factor 2, as shown on theright, and repeat the experiment. Comparedto the angular speed in the first situation, thenew angular speed is

1. twice as high 3. half as much2. the same 4. none of the above

A figure skater stands on one spot on the ice(assumed frictionless) and spins around withher arms extended. When she pulls in herarms, she reduces her rotational inertia andher angular speed increases so that her angularmomentum is conserved. Compared to herinitial rotational kinetic energy, her rotationalkinetic energy after she has pulled in herarms must be1. the same.2. larger because she’s rotating faster.3. smaller since her rotational inertia is smaller.

Two wheels with fixed hubs, each having amass of 1 kg, start from rest, and forces areapplied as shown. Assume the hubs andspokes are massless, so that the rotational inertiais I = mR2. In order to impart identicalangular accelerations, how large must F2 be?

1. 0.25 N2. 0.5 N3. 1 N4. 2 N5. 4 N

Consider the uniformly rotating objectshown below. If the object’s angular velocityis a vector (in other words, it points in acertain direction in space) is there a particulardirection we should associate with theangular velocity?

1. yes, ±x2. yes, ±y3. yes, ±z4. yes, some other direction5. no, the choice is really arbitrary

A person spins a tennis ball on a string in ahorizontal circle (so that the axis of rotationis vertical). At the point indicated below, theball is given a sharp blow in the forward direction. This causes a change in angular momentum ΔL in the

1. x direction2. y direction3. z direction

A person spins a tennis ball on a string in ahorizontal circle (so that the axis of rotation isvertical). At the point indicated below, the ballis given a sharp blow vertically downward. Inwhich direction does the axis of rotation tiltafter the blow?

1. +x direction2. –x direction3. +y direction4. –y direction5. It stays the same (but the magnitude ofthe angular momentum changes).6. The ball starts wobbling in all directions.

A suitcase containing a spinning flywheel isrotated about the vertical axis as shown in(a). As it rotates, the bottom of the suitcasemoves out and up, as in (b). From this, wecan conclude that the flywheel, as seen fromthe side of the suitcase as in (a), rotates

1. clockwise.2. counterclockwise.