Ch 8 Quiz practice

Center of mass

Toss a baseball bat into the air and it wobbles about its

None of the above

A 1-kg rock is suspended from the tip of a horizontal meterstick at the 0-cm mark so that the meterstick barely balances like a seesaw when its fulcrum is at the 12.5-cm mark. From this information, the mass of the meterstick is

An unbalanced torque

A ball gains speed while rolling down a hill due mainly to

The boy

A boy plays solitary seesaw by placing the seesaw's fulcrum one-eighth the distance from where he sits at one end. Which weighs more?

Sphere

A ring, a disk, and a solid sphere begin rolling down a hill together. Which reaches the bottom first?

More than the weight of the seesaw

A solitary boy cannot balance on a seesaw with its fulcrum at its midpoint. If the fulcrum is moved to one-quarter the distance from the boy, balance is achieved when the weight of the boy is

4 m

A swimming area in a rotating space habitat is located in a region of 1/4 g. If a diver can jump 1 m high in a 1-g region, how high can the same diver jump in the swimming area?

Droops

A tightrope walker more easily balances on a tight wire if her pole

Rotation

A torque acting on an object tends to produce

At the top, away from your hand

A vertically-held sledge hammer is easier to balance when the heavier end is

Basketball

Which of these has its center of mass where no mass exists?

Rotating

Centrifugal forces are an apparent reality to observers in a reference frame that is

Centripetal force has no component in the direction of motion

Centripetal force does no work on a circularly-moving object because

Two times greater

Consider two flywheels of the same size and shape, but one with twice the mass. Rotational inertia of the more massive one is

Torque

If Alex wishes to rotate his skateboard, then he must apply a

At the center of the Earth

If Earth had a pair of identical moons on opposite sides of the same circular orbit, the center of gravity of the double-moon-Earth system would be

Double

If a turntable's rotational speed is doubled, then the linear speed of a pet hamster sitting on the edge of the record will

Bristles part

If you balance a broom horizontally on one finger, the center of gravity of the broom will be above your finger, closer to the bristles end than the handle end. If you saw the broom in two pieces at that point and weigh the two parts on a scale, you'll find that the heavier part is the

Two

If you place a pipe over the end of a wrench when trying to rotate a stubborn bolt, effectively making the wrench handle twice as long, you'll multiply the torque by

1/3 the distance from the fulcrum

On a balanced seesaw, a boy three times as heavy as his partner sits

Bristles end

Stand a broom upright on the end of its pole and let it topple to the floor. Repeat, but with the bristles end on the floor. The faster fall will be the broom standing on its

Longer

Stand a meterstick on its end and let it rotate to the floor. If you attach a heavy glob of clay to its upper end and repeat, the time to fall will be

circular path

The bob of a conical pendulum swings in a

Changes as a person bends over

The center of mass of a human body is located at a point that

Slows

The chef at the infamous Fattening Tower of Pizza tosses a spinning disk of uncooked pizza dough into the air. The disk becomes wider during its flight, while its rotational speed

Above a place of support

The famous Leaning Tower of Pisa doesn't topple over because its center of gravity is

The radial component of the normal force.

The force responsible for a car moving steadily along a no-friction icy banked curve is due to

g

The gravitational field simulated by rotation in a space habitat that is best suited for humans is

Spin of the Earth

The main reason a person weighs less at the equator than at the poles involves the

Directed toward the center of the curve

The net force exerted on a car traveling in a circular path at constant speed is

Travel at different linear speeds for the same rotational speed, in effect vary their diameters. Both of these.

The tapered shape of the wheel rims that ride on railroad tracks allows opposite wheels to

Through its center of gravity

To kick a football so it won't topple end over end, kick it so the force of impact extends

Rise

Two people are balanced on a seesaw. If one person leans inward toward the center of the seesaw, that person's end of the seesaw tends to

Cover different distances per revolution

When a train makes a curve, a tapered wheel rim is able to

Increases

When a twirling ice skater brings her arms inward, her rotational speed

Directly above the point between wheels below

When riding at constant velocity on a Segway electric vehicle, your center of mass is

The filled jar

Which jar will roll down an incline in the shortest time, an empty one or one filled with peanut butter?

Mouse

Which of these animals has a quicker stride?

The same.

You can safely stand on the overhanging end of a heavy plank that rests on a table. How much overhang depends on your mass and the plank's mass. If you can stand on the end of a plank that overhangs the edge of the supporting table 1/4 its total length, how massive is the plank compared to your mass?