Physics Chapter 10

A space habitat is designed so that the variation in g between a person's head and feet is less than 0.01 g. If the person is 2 m tall, then the radius of the habitat is... A. 2000 m B. 200 m C. 20 m D. more than 2000 m

B. 200 m

At the outer edge of a rotating habitat, 130m from its center, the rotational acceleration is g. What is the rotational acceleration at a distance of 65 m from the center of the habitat. A. 2x g B. 1/3 g C. 4x g D. 1/2 g

D. 1/2 g

You sit at the outer rim of a ferris wheel that rotates at 22 revolutions per minute (RPM). What would your rotational speed be if you were instead clinging to a position half- way from the center to the outer rim? A. 11 RPM'S B. 2 RPM'S C. 44 RPM's D. 22 RPM's

D. 22 RPM'S

Earth Rotates in a/ an_________direction. A. Elliptical B. Circular vector C. Clockwise D. Counter Clockwise

D. Counter Clockwise

What is the direction of the force that acs on clothes in the spin cycle of a washing machine? A. Up B. Down C. Outward D. Inward

D. Inward

"Centrifugal forces" are an apparent reality to observers in a reference frame that is ... A. At rest B. An intertial reference frame C. Moving at a constant velocity D. Rotating E. Bouncing

D. Rotating

It is possible to rotate a very large cylindrical space habitat around its central axis at just the right speed so people living inside the cylinder will experience a force that feels like gravity.

True

Ladybugs on the inside of a spinning bicycle tire can experience a force that feels like gravity to them.

True

Linear speed is called tangential speed when something moves in a circle.

True

The angular speed of a wheel is defined as the number of rotations it makes in a unit of time.

True

The only reason riders on a rotating platform in a carnival ride don't fall out is because centripedal forces are acting upon them. T or F.

True

When an object turns about an internal axis, the motion is called rotation.

True

When you whirl a can on the end of a string, the centripetal force on the can is actually the pull of the string.

True

Tapered rims on a railroad train wheels enable to round curves without any wheels skidding. Consider a curve with the outer track is one part in 25 linger than the inner track. The wide part of the rim should have a diameter wider than the narrow part by at least one part to____. A. 25 B. 50 C. 12.5 D. 2

A. 25

A vertical pole standing against a wall topples to the ground and the center of the pole has a speed of 26 m/s as it hits the ground. With what speed does the far end of the pole hit the ground? A. 52 m/s B. 26 m/s C. 39 m/s D. 13 m/s

A. 52 m/s

If Earth rotated faster about its axis, your weight would A. Decrease B. Increase C. Stay the same.

A. Decreases

If you whirl a ball on the end of a string and the string suddenly breaks, the ball will.... A. Fly off, tangent to its circular path. B. Fly directly toward you. C. Spiral away from your hand. D. Fly directly away from you. E. Spiral in toward your hand.

A. Fly off, tangent to its circular path.

When a railroad train rounds a banked track, the centripetal force needed comes not from friction, but from the... A. Horizontal component of the normal force. B. Normal force. C. Vertical component of the normal force. D. None of the above.

A. Horizontal component of normal force.

Which of the following is not a unit of rotational speed? A. Miles per hour B. Revolutions per minute C. Rotations per minute D. Rotations per second E. Revolutions per second

A. Miles Per Hour

A person weighs less at the equator than at the poles. The reason for this has to do with the... A. Spin of the Earth. B. Influence of the sun, moon, and all of the planets. C. Tidal bulges. D. Higher temperatures at the equator, and the expansion of matter. E. Too much thanksgiving dinner.

A. Spin of the earth.

Which has greater linear speed, a horse near the outside rail of a merry go round or a horse near the inside rail? A.The outside horse B. Neither- they both have the same speed C. The inside horse

A. The outside horse

Stunt motorcyclist Biker Harry rides his bike inside a futuristic rotating space station- a giant rotating donut- shaped structure in space. The normal support force feels like weight to him. As he rides his bike in the opposite direction to the station's rotation, the normal force... A. Increases B. Decreases C. Remains the same

B. Decreases

As the rotation speed of a space habitat increases, the weight of the people inside... A. Stays the same B. Increases C. Decreases

B. Increases

A race car travels in a circle with a constant speed. The net force on the race car... A. Is zero because the race car is not accelerating. B. Is directed towards the center of the curve. C. Is directed forward in the direction of travel. D. none of the above.

B. Is directed towards the center of the curve.

To weigh less in the Southern Hemisphere, you should go... A. West B. North C. East D. South

B. North

The centripetal force exerted on stunt motorcyclist Biker Bruno while riding on the inner vertical surface of a circular track is A. His weight B. The normal force C. Friction D. None of the above

B. The normal force

A possible space habitat of the future is a cylinder in space rotating about its long axis. What is the relative gravitational field along the axis of the habitat? A. Three- Quarters G B. Zero C. One- Quarter G D. One- Half G E. G

B. Zero

The tangential speed of the outer rim of a ferris wheel is 30 m/s. What is the tangential speed of a position half- way from the center to the outer rim. A. 20 m/s B. 60 m/s C. 15 m/s D. 10 m/s

C. 15 m/s

A game room in a rotating space habitat is located in a 0.25-g region. If a person can jump 0.5-m high in a 1-g region, how high can the same person jump in the game room? A. 8 m B. 4 m C. 2 m D. More than 8 m E. 0.5 m

C. 2 m

Newbs Newton swings a rock into a circular path while holding an attached string overhead. The string makes a 45- degree angle to the vertical (compromising a "concial pendulum"). The centripetal force that holds the rock in its circular path is the.... A. Tension in the string. B. Vertical component of the string tension. C. Horizontal component of the String tension. D. None of the above.

C. Horizontal component of the String tension.

Stunt motorcyclist Biker Pete rides his bike inside a futuristic rotation space station- a giant rotation donut- shaped structure in space. The normal support feels like weight to him. As he rides his bike in the same direction that the station rotates, the normal force. A. Remains unaffected B. Decreases C. Increases

C. Increases

Nick Spacewalker hovers in space beside a rotating space station in outer space. Both he and the center of mass of the space station are at relative rest. If the space station is in Earth's orbit, than Nick A. may or may not be in Earth orbit. B. is not in Earth's orbit. C. Is also in Earth's orbit.

C. Is also in Earth's orbit.

Which has greater angular speed, a horse near the outside rail of the merry go round or a horse near the inside rail? A. The outside horse B. The inside horse C. Neither- they both have the same angular speed

C. Neither- they both have the same angular speed

A worm rests on the bottom of a tin can that is being whirled horizontally on the end of a string. Since the worm, like the tin can, moves in a circle, there must be a force on it. What exerts this force? A. Gravity B. Your hand C. The tin can D. The String E. There is no force acting on it.

C. The tin can

A rock whirled on the end of a string moves in a circle because... A. Once the rock starts moving, that is its natural tendency. B. The rock continually pulls on the string. C. There is an inward force acting on the rock. D. There is a force on the rock pulling it outward. E. All of the above.

C. There is an inward force acting on the rock.

Earth rotates and revolves through space. Earth rotates about the ___, which is an ___ axis. Earth revolves about the ___, which is ___ axis. A. sun, external, north/south pole, internal. B. north/south pole, external, sun, internal. C. north/south pole, internal, sun, external. D. sun, internal, north/south pole, external.

C. north/south pole, internal, sun, external.

People in the future may well live inside a rotating space structure that is more than 2 km in diameter. Inside the structure, people on the inside of the outer edge will experience 1 g while people halfway to the axis will experience A. 1 g B. 0 g C. 1/4 g D. 2 g E. 1/2 g

E. 1/2 g

A bug on a turning phonograph record will make more turns per minute if it is located toward the outer edge of the record.

False

Any force that causes an object to move in a circular path is called inertial force.

False

A straight line about which rotation takes place is called an axis.

True