Conceptual Physics: Questions On Rotational Motion

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  • 1/61 Questions

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

    • Increases.
    • Decreases.
    • Remains the same.
Please wait...
About This Quiz

Explore the dynamics of rotational motion with this engaging quiz on Conceptual Physics. Assess your understanding of linear and angular speeds through practical examples like merry-go-rounds, record players, and railroad trains. Ideal for learners seeking to deepen their knowledge of physics.

Conceptual Physics: Questions On Rotational Motion - Quiz

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  • 2. 

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

    • Geometrical center

    • Center of mass

    • Heavier end

    Correct Answer
    A. Center of mass
    Explanation
    When a baseball bat is tossed into the air, it wobbles about its center of mass. The center of mass is the point where the mass of an object is evenly distributed. In the case of the bat, the center of mass is the point where the bat would balance perfectly if it were placed on a fulcrum. As the bat rotates in the air, it wobbles around this point due to the uneven distribution of mass along its length. The heavier end of the bat does not necessarily determine the center of mass, as it depends on the distribution of mass along the entire length of the bat.

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  • 3. 
    If the Earth had two identical moons in one circular orbit, and the moons were as far apart in that orbit as they could be, the center of gravity of the Earth-moons system would be - ProProfs

    If the Earth had two identical moons in one circular orbit, and the moons were as far apart in that orbit as they could be, the center of gravity of the Earth-moons system would be

    • At the center of the Earth.

    • Inside the Earth, but off center.

    • Outside the Earth, but within the orbital path of the moons.

    • Outside the Earth, but beyond the orbital path of the moons.

    Correct Answer
    A. At the center of the Earth.
    Explanation
    If the Earth had two identical moons in one circular orbit and they were as far apart as possible, the center of gravity of the Earth-moons system would be at the center of the Earth. This is because the center of gravity is the point where the gravitational forces acting on the system balance out. In this scenario, the gravitational forces from the two moons would be equal and opposite, causing them to cancel each other out and resulting in the center of gravity being at the center of the Earth.

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  • 4. 

    A torque acting on an object tends to produce

    • Equilibrium

    • Rotation

    • Linear motion

    • Velocity

    • A center of gravity

    Correct Answer
    A. Rotation
    Explanation
    When a torque acts on an object, it creates a rotational force that tends to make the object rotate around a fixed point or axis. This is why the correct answer is rotation. Torque is the product of force and the perpendicular distance from the axis of rotation, and it causes objects to rotate rather than move in a linear motion or change their center of gravity. Equilibrium refers to a state of balance, and velocity is the speed and direction of an object's motion, but neither directly relate to the effect of torque on an object.

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  • 5. 

    The center of gravity of a circular disk of sheet metal is

    • At the center of the disk.

    • Midway between the center and the outside.

    • Two-thirds of the way between the center and the outside.

    • Impossible to predict without knowing the metal density.

    Correct Answer
    A. At the center of the disk.
    Explanation
    The center of gravity of a circular disk of sheet metal is at the center of the disk because the shape is symmetrical and the weight is evenly distributed around the center. Therefore, the gravitational forces acting on each part of the disk cancel each other out, resulting in the center of gravity being located at the center of the disk.

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  • 6. 

    Horses that move with the fastest linear speed on a merry-go-round are located

    • Near the center

    • Near the outside

    • Anywhere, because they all move at the same speed

    Correct Answer
    A. Near the outside
    Explanation
    Horses that are located near the outside of a merry-go-round move with the fastest linear speed because they have to cover a greater distance in the same amount of time compared to horses located near the center. As the merry-go-round rotates, the horses on the outside have to travel a larger circumference, resulting in a higher linear speed. On the other hand, horses near the center have a smaller circumference to cover, so their linear speed is slower. Therefore, the horses near the outside of the merry-go-round move with the fastest linear speed.

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  • 7. 

    A huge rotating cloud of particles in space gravitate together to form an increasingly dense ball. As it shrinks in size, the cloud

    • Rotates faster.

    • Rotates slower.

    • Rotates at the same speed.

    • Cannot rotate.

    Correct Answer
    A. Rotates faster.
    Explanation
    As the cloud of particles in space gravitates together to form a denser ball, the conservation of angular momentum causes it to rotate faster. This is due to the principle of conservation of angular momentum, which states that the product of an object's moment of inertia and its angular velocity remains constant unless acted upon by an external torque. As the cloud shrinks in size, its moment of inertia decreases, causing its angular velocity to increase, resulting in faster rotation.

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  • 8. 

    When a train makes a curve, different parts of the wheel rims

    • Cover a different distance in the same time

    • Must all expand at the same time

    • Must all contract at the same time

    • Vibrate at different rates

    Correct Answer
    A. Cover a different distance in the same time
    Explanation
    When a train makes a curve, different parts of the wheel rims cover a different distance in the same time because the outer part of the wheel has to travel a larger circumference compared to the inner part. As a result, the outer part of the wheel covers a greater distance in the same time as the inner part. This difference in distance covered is necessary to ensure that the train can smoothly navigate the curve without derailing.

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  • 9. 

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

    • Above its center of gravity.

    • Through its center of gravity.

    • Below its center of gravity

    Correct Answer
    A. Through its center of gravity.
    Explanation
    When a football is kicked through its center of gravity, the force of impact is evenly distributed throughout the ball. This prevents it from toppling end over end because there is no imbalance in the forces acting on it. Kicking the ball above or below its center of gravity would create an uneven distribution of force, causing the ball to rotate and potentially topple. Therefore, kicking through the center of gravity ensures a stable trajectory for the football.

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  • 10. 

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

    • 1/3 the distance from the fulcrum

    • Less than 1/3 the distance from the fulcrum

    • More than 1/3 the distance from the fulcrum

    Correct Answer
    A. 1/3 the distance from the fulcrum
    Explanation
    The boy, being three times as heavy as his partner, needs to sit closer to the fulcrum in order to balance the seesaw. If he sat more than 1/3 the distance from the fulcrum, his weight would have a greater lever arm and the seesaw would be unbalanced. Therefore, he must sit 1/3 the distance from the fulcrum to maintain balance.

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  • 11. 

    Your pet hamster sits on a record player whose angular speed is constant. If he moves to a point twice as far from the center, then his linear speed

    • Doubles

    • Halves

    • Remains the same

    Correct Answer
    A. Doubles
    Explanation
    When the hamster moves to a point that is twice as far from the center of the record player, its linear speed will double. This is because linear speed is directly proportional to the distance from the center of rotation. As the hamster moves to a point twice as far from the center, the distance it covers in a given time also doubles, resulting in a doubling of its linear speed.

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  • 12. 

    Which moves faster in m/s on a merry-go-round: a horse on the inside or a horse on the outside near the outer rail?

    • Inside horse

    • Outside horse

    • Both move at the same speed in m/s

    Correct Answer
    A. Outside horse
    Explanation
    The outside horse moves faster in m/s on a merry-go-round compared to the inside horse. This is because the outside horse has to travel a larger circumference than the inside horse in the same amount of time. Since speed is defined as distance traveled per unit of time, the outside horse covers a greater distance in the same time period, resulting in a higher speed.

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  • 13. 

    Consider a string with several rocks tied along its length at equally spaced intervals. You whirl the string overhead so that the rocks follow circular paths. Compared to a rock in the middle of the string, a rock at the outer end moves

    • Half as fast

    • Twice as fast

    • At the same linear speed

    Correct Answer
    A. Twice as fast
    Explanation
    A rock at the outer end of the string moves twice as fast compared to a rock in the middle of the string because it has a larger circumference to cover in the same amount of time. As the string is whirled overhead, the outer rock has to travel a longer distance in the same period of time, resulting in a higher speed.

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  • 14. 

    When doing somersaults, you'll more easily rotate when your body is

    • Straight with both arms above your head.

    • Straight with both arms at your sides.

    • Balled up.

    • No difference

    Correct Answer
    A. Balled up.
    Explanation
    When doing somersaults, you'll more easily rotate when your body is balled up. This is because when your body is balled up, your mass is concentrated in a smaller area, which allows for faster rotation due to the conservation of angular momentum. Additionally, when your body is balled up, it creates a smaller moment of inertia, making it easier to rotate. Having both arms above your head or at your sides would not provide the same level of compactness and concentration of mass, therefore making it more difficult to rotate.

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  • 15. 

    Put a pipe over the end of a wrench when trying to turn a stubborn nut on a bolt, to effectively make the wrench handle twice as long, you'll multiply the torque by

    • Two

    • Four

    • Eight

    Correct Answer
    A. Two
    Explanation
    By putting a pipe over the end of a wrench, the length of the wrench handle effectively doubles. This longer lever arm increases the torque applied to the nut. Since torque is directly proportional to the length of the lever arm, multiplying the length by two will also multiply the torque by two. Therefore, the correct answer is two.

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  • 16. 

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

    • Rise.

    • Fall.

    • Stay at the same level.

    • Rise and then fall.

    • Fall and then rise

    Correct Answer
    A. Rise.
    Explanation
    When one person leans toward the center of the seesaw, their end of the seesaw will rise. This is because the person's weight is shifting closer to the center of the seesaw, reducing the downward force on their end. As a result, the other end of the seesaw, which has less weight on it, will rise.

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  • 17. 

    A person weighs less at the equator than at the poles. The main reason for this has to do with

    • The spin of the Earth.

    • The shape of the Earth.

    • The influence of the sun, moon, and all the planets.

    • The law of action and reaction.

    Correct Answer
    A. The spin of the Earth.
    Explanation
    The correct answer is the spin of the Earth. As the Earth rotates, it bulges at the equator due to centrifugal force. This bulge causes a slight decrease in gravitational pull at the equator compared to the poles, resulting in a slightly lower weight for a person at the equator. The shape of the Earth and the influence of celestial bodies do have some impact on weight, but the main reason for the weight difference is the Earth's spin.

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  • 18. 

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

    • 1 m

    • 2 m

    • 4 m

    • 16 m

    • More than 16 m

    Correct Answer
    A. 4 m
    Explanation
    In a 1/4 g region, the force of gravity is only 1/4 of what it is in a 1 g region. Since the diver can jump 1 m high in a 1 g region, the force of gravity is enough to make the diver reach that height. In the swimming area with 1/4 g, the force of gravity is weaker, so the diver will be able to jump higher. If the force of gravity is only 1/4 of what it is in a 1 g region, then the diver can jump 4 times higher. Therefore, the diver can jump 4 m high in the swimming area.

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  • 19. 

    The gravitational field best suited for humans living in an outer space colony is

    • Zero.

    • G.

    • One-quarter g.

    • One-half g.

    • Three-quarters g.

    Correct Answer
    A. G.
    Explanation
    The correct answer is g. Humans living in an outer space colony would be best suited with a gravitational field equal to that of Earth, which is denoted as g. This level of gravity is what humans are accustomed to and is necessary for maintaining normal bodily functions and preventing the negative effects of long-term exposure to microgravity, such as bone and muscle loss.

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  • 20. 

    A coin and a ring roll down an incline starting at the same time. The one to reach the bottom first will be the

    • Ring

    • Coin

    • Both reach the bottom at the same time

    Correct Answer
    A. Coin
    Explanation
    The coin will reach the bottom first because it has a smaller mass compared to the ring. As they both roll down the incline, the coin will experience less resistance and therefore accelerate faster. This means that the coin will cover the distance to the bottom in a shorter amount of time compared to the ring.

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  • 21. 

    A car travels in a circle with constant speed. The net force on the car is

    • Directed forward, in the direction of travel.

    • Directed toward the center of the curve.

    • Zero because the car is not accelerating.

    • None of these

    Correct Answer
    A. Directed toward the center of the curve.
    Explanation
    When a car travels in a circle with constant speed, it is constantly changing its direction. According to Newton's second law of motion, an object will experience a net force when it undergoes acceleration. In this case, the car is constantly changing its direction, which means it is undergoing acceleration. Therefore, there must be a net force acting on the car. Since the car is moving in a circle, the net force must be directed toward the center of the curve, allowing the car to continuously change its direction and maintain its circular motion.

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  • 22. 

    Neglecting air resistance, which will roll from rest to the bottom of an incline first, an empty jar, or the same jar filled with peanut butter?

    • The filled jar

    • The empty jar

    • Both reach the bottom at the same time.

    • More information is needed.

    Correct Answer
    A. The filled jar
    Explanation
    The filled jar will roll from rest to the bottom of the incline first because it has more mass compared to the empty jar. According to Newton's second law of motion, the acceleration of an object is directly proportional to its mass. Therefore, the filled jar will experience a greater force of gravity pulling it down the incline, resulting in a faster acceleration and reaching the bottom first.

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  • 23. 

    Suppose the circumference of a bicycle wheel is 2 meters. If it rotates at 1 revolution per second when you are riding the bicycle, then your speed will be

    • 1 m/s

    • 2 m/s

    • 3 m/s

    • 3.14 m/s

    • 6.28 m/s

    Correct Answer
    A. 2 m/s
    Explanation
    The circumference of the bicycle wheel is 2 meters. When the wheel rotates at 1 revolution per second, it means that the wheel covers a distance equal to its circumference in 1 second. Therefore, the speed of the bicycle will be equal to the circumference of the wheel, which is 2 meters, per second. Hence, the correct answer is 2 m/s.

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  • 24. 

    The long, heavy tail of a spider monkey enables the monkey to easily vary its

    • Weight

    • Momentum

    • Inertia

    • Center of gravity

    • None of these

    Correct Answer
    A. Center of gravity
    Explanation
    The long, heavy tail of a spider monkey enables the monkey to easily vary its center of gravity. The center of gravity is the point at which the weight of an object or organism is evenly distributed. By moving its tail, the spider monkey can shift its center of gravity, allowing it to maintain balance and stability while navigating through trees and swinging from branches. This adaptation is crucial for the monkey's arboreal lifestyle and helps it move efficiently in its environment.

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  • 25. 

    A flywheel's mass is twice that of another of the same size and shape. The more massive flywheel's rotational inertia is

    • Four times the other's.

    • Two times the other's.

    • The same as the other's.

    • Half the other's.

    Correct Answer
    A. Two times the other's.
    Explanation
    The rotational inertia of a flywheel is directly proportional to its mass. Since the more massive flywheel has a mass that is twice that of the other flywheel, its rotational inertia will also be twice as much. Therefore, the correct answer is that the more massive flywheel's rotational inertia is two times the other's.

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  • 26. 

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

    • Double

    • Double

    • Remain the same

    Correct Answer
    A. Double
    Explanation
    When a turntable's rotational speed is doubled, it means that it is rotating at a faster rate. Since the pet hamster is sitting on the edge of the record, which is attached to the turntable, it will also experience this increase in rotational speed. This increase in rotational speed directly translates to an increase in linear speed for the hamster. Therefore, the linear speed of the hamster will double.

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  • 27. 

    An industrial flywheel has a greater rotational inertia when most of its mass is

    • Nearest the rim

    • Nearest the axis

    • Uniformly spread out as in a disk

    Correct Answer
    A. Nearest the rim
    Explanation
    When most of the mass of an industrial flywheel is located nearest the rim, it increases the flywheel's rotational inertia. Rotational inertia, also known as moment of inertia, is a measure of an object's resistance to changes in its rotational motion. By placing the mass near the rim, the flywheel's rotational inertia is increased because the mass is located farther away from the axis of rotation. This increases the object's resistance to changes in its rotational speed, making it harder to accelerate or decelerate.

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  • 28. 

    What is the simulated gravitational field strength half-way between the axis of the Earth and the outside edge where the field strength is g?

    • Zero

    • G

    • One-half g

    • Three-quarters g

    Correct Answer
    A. One-half g
    Explanation
    The simulated gravitational field strength halfway between the axis of the Earth and the outside edge where the field strength is g would be one-half g. This is because the gravitational field strength decreases as you move away from the center of the Earth. At the axis, the field strength is g, but halfway between the axis and the outside edge, the field strength would be half of g.

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  • 29. 

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

    • In effect, vary their diameters

    • Travel at different linear speeds for the same rotational speed

    • Both A and B are correct

    Correct Answer
    A. Both A and B are correct
    Explanation
    The tapered shape of the parts of the wheels that ride on railroad tracks allows opposite wheels to vary their diameters. This is because the tapered shape causes the wheels to have different radii at different points, allowing them to effectively change their diameters. As a result, when the wheels rotate at the same speed, they will travel at different linear speeds. Therefore, both statement A and B are correct.

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  • 30. 

    A ring, a disk, and a solid sphere begin rolling down a hill together. The one to reach the bottom first is the

    • Ring

    • Disk

    • Sphere

    • They all reach the bottom at the same time.

    • Not enough information is given.

    Correct Answer
    A. Sphere
    Explanation
    The solid sphere will reach the bottom first because it has the most mass and therefore the most momentum. The ring and the disk will have less mass and momentum, causing them to reach the bottom later than the sphere.

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  • 31. 

    A small boy places a rock under the middle of a of a long wood plank, sits near one end and his mother sits near the opposite end. To balance each other

    • The mother should move further away from the boy.

    • The boy should move closer to his mother.

    • Both should move closer to the ends of the plank.

    • Both should move closer to the middle of the plank.

    • None of the above choices would work.

    Correct Answer
    A. None of the above choices would work.
    Explanation
    In order for the boy and his mother to balance each other, their weights must be equal and their distances from the pivot point (the rock) must be equal. If the mother moves further away from the boy, her weight will have a greater lever arm and she will exert a greater torque, causing the plank to tilt towards her. Similarly, if the boy moves closer to his mother, his weight will have a smaller lever arm and he will exert a smaller torque, causing the plank to tilt towards his mother. Moving closer to the ends or the middle of the plank would also disrupt the balance. Therefore, none of the above choices would work.

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  • 32. 

    Suppose you put very large-diameter tires on your car. Then, your speedometer will show a speed that is

    • Higher than it is actually.

    • Lower than it is actually.

    • The same as before.

    Correct Answer
    A. Lower than it is actually.
    Explanation
    When you put very large-diameter tires on your car, the circumference of the tires increases. This means that for each rotation of the tire, the car will travel a greater distance compared to when it had smaller tires. However, the speedometer is calibrated based on the assumption that the car has the standard-sized tires. As a result, the speedometer will still measure the rotations of the tires, but it will incorrectly calculate the speed based on the assumption of the original tire size. Therefore, the speedometer will show a speed that is lower than it is actually.

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  • 33. 

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

    • Remains constant.

    • Increases.

    • Decreases.

    Correct Answer
    A. Decreases.
    Explanation
    As the chef tosses the spinning disk of uncooked pizza dough into the air, the diameter of the disk increases. This means that the dough is spreading out and becoming thinner as it flies through the air. In order to conserve angular momentum, the rotational speed of the disk must decrease as the diameter increases. This is similar to how an ice skater spins slower when they extend their arms outwards. Therefore, the correct answer is that the rotational speed of the dough decreases.

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  • 34. 

    A ring and a disk, initially at rest, roll down a hill together. The one to reach the bottom first

    • Is the ring.

    • Is the disk

    • Depends on the masses.

    • Depends on the relative rotational inertias.

    • Both reach the bottom at the same time.

    Correct Answer
    A. Is the disk
    Explanation
    The disk will reach the bottom first because it has a greater rotational inertia compared to the ring. Rotational inertia depends on the distribution of mass around the axis of rotation. The disk has more mass spread out at a greater distance from the axis, resulting in a larger rotational inertia. This means that it will resist changes in its rotational motion more than the ring, allowing it to roll down the hill faster and reach the bottom first.

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  • 35. 

    The rotational inertia of your leg is greater when your leg is

    • Straight

    • Bent

    • Same either way

    Correct Answer
    A. Straight
    Explanation
    When your leg is straight, it has a greater rotational inertia compared to when it is bent. Rotational inertia is a measure of an object's resistance to changes in its rotational motion. When your leg is straight, it has a longer moment arm, which is the distance between the axis of rotation and the mass of the object. This longer moment arm increases the rotational inertia of your leg, making it more difficult to rotate or change its rotational motion. On the other hand, when your leg is bent, the moment arm is shorter, resulting in a lower rotational inertia.

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  • 36. 

    A tightrope walker more easily balances on a tightwire if his pole

    • Is held high.

    • Droops.

    • Is short but heavy.

    Correct Answer
    A. Droops.
    Explanation
    The correct answer is "droops." When a tightrope walker's pole droops, it lowers the center of gravity, making it easier for the walker to maintain balance. This allows them to counteract any potential tipping or swaying movements and stay stable on the tightwire. Holding the pole high would raise the center of gravity, making it more difficult to balance, while a short but heavy pole would not have the same effect as a drooping pole.

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  • 37. 

    Strictly speaking, to weigh less in the Northern Hemisphere, you should move to a location further

    • North (toward the pole).

    • South (toward the equator).

    • East.

    • West.

    Correct Answer
    A. South (toward the equator).
    Explanation
    Moving towards the equator would make you weigh less in the Northern Hemisphere because the Earth's rotation causes a centrifugal force that is strongest at the equator. This force counteracts the gravitational force, making you weigh slightly less. As you move further south towards the equator, the centrifugal force increases, resulting in a decrease in weight.

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  • 38. 

    Since each rolling wheel of a railroad train is tapered, the narrow part of the wheel has a tangential speed that is

    • Greater than that of the wide part

    • Smaller than that of the wide part

    • The same as that of the wide part

    Correct Answer
    A. Smaller than that of the wide part
    Explanation
    The correct answer is "smaller than that of the wide part". This is because the tapered shape of the wheel causes the circumference to decrease towards the narrow part. As a result, the distance covered by the narrow part in one rotation is smaller than that covered by the wide part. Since the speed is defined as the distance covered per unit time, the narrow part of the wheel will have a smaller tangential speed compared to the wide part.

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  • 39. 

    A flywheel's diameter is twice that of another of the same shape and mass. The larger flywheel's rotational inertia is

    • Four times the other's.

    • Two times the other's.

    • The same as the other's.

    • Half the other's.

    Correct Answer
    A. Four times the other's.
    Explanation
    The rotational inertia of a flywheel is directly proportional to the square of its diameter. Since the diameter of the larger flywheel is twice that of the smaller flywheel, its rotational inertia will be four times greater.

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  • 40. 

    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

    • Bristles part.

    • Handle part.

    • Both the same weight

    Correct Answer
    A. Bristles part.
    Explanation
    When balancing a broom horizontally on one finger, the center of gravity is the point where the weight of the broom is evenly distributed. Since the broom is balanced on the finger, the center of gravity must be directly above the finger. This means that the heavier part of the broom, which is closer to the bristles end, will be above the finger. Therefore, when the broom is sawed in two pieces at that point and weighed on a scale, the heavier part will be the bristles part.

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  • 41. 

    For a system in mechanical equilibrium

    • The resultant force must be zero.

    • The resultant torques must be zero.

    • The resultant forces and torques must both be zero.

    • The resultant forces and torques must be equal.

    Correct Answer
    A. The resultant forces and torques must both be zero.
    Explanation
    In a system in mechanical equilibrium, the forces and torques acting on the system must both be zero. This means that the net force on the system is zero, indicating that the system is not accelerating in any direction. Additionally, the net torque on the system is zero, meaning that there is no rotational acceleration. Therefore, for a system to be in mechanical equilibrium, both the resultant forces and torques acting on it must be zero.

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  • 42. 

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

    • Moving at constant velocity.

    • An inertial reference frame.

    • At rest.

    • Rotating.

    • None of these

    Correct Answer
    A. Rotating.
    Explanation
    The statement "Centrifugal forces are an apparent reality to observers in a reference frame that is rotating" means that when an observer is in a reference frame that is rotating, they will perceive centrifugal forces. Centrifugal forces are the apparent outward forces experienced by objects in a rotating frame of reference, even though they are not actual forces. This is due to the inertia of the objects wanting to move in a straight line while the rotating frame of reference pulls them outward. Therefore, the correct answer is rotating.

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  • 43. 

    If the polar icecaps melted, the resulting water would spread over the entire Earth. This new mass distribution would tend to make the length of a day

    • Longer.

    • Shorter.

    • Stay the same.

    • Shorter at first, then longer.

    • Longer at first, then shorter.

    Correct Answer
    A. Longer.
    Explanation
    If the polar icecaps melted, the resulting water would spread over the entire Earth. This would increase the total mass of the Earth, leading to a redistribution of mass. According to the law of conservation of angular momentum, when the mass distribution changes, the rotation of the Earth slows down, resulting in a longer day. Therefore, if the polar icecaps melted, the length of a day would become longer.

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  • 44. 

    A baseball bat is balanced on a fulcrum. The center of gravity of the bat is located

    • Closer to the handgrip.

    • Above the fulcrum.

    • Near the heavy end.

    Correct Answer
    A. Above the fulcrum.
    Explanation
    The center of gravity of a baseball bat is located above the fulcrum because the bat is heavier towards the end where the hitting surface is. This causes the center of gravity to be closer to the heavy end, resulting in it being positioned above the fulcrum.

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  • 45. 

    Which will roll down an incline in the shortest time, a can filled with water or the same can filled with ice?

    • Water

    • Ice

    • Both the same

    • Not enough information is given.

    Correct Answer
    A. Water
    Explanation
    The can filled with water will roll down the incline in the shortest time because water has a higher density compared to ice. This means that the can filled with water will have more mass, leading to a greater force of gravity acting on it. As a result, the can filled with water will accelerate faster and reach the bottom of the incline in the shortest time.

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  • 46. 

    Consider a bowling alley inside a rotating space torus (huge "donut"). Compared to your bowling experience on earth, you will notice that the ball

    • Consider a bowling alley inside a rotating space torus (huge "donut"). Compared to your bowling experience on earth, you will notice that the ball

    • Feels heavier when you throw it in the direction of the moving alley, and lighter when you throw it in the opposite direction.

    • Veers to the right when you throw it in the direction of the moving alley, and to the left when you throw it in the opposite direction.

    • None of these

    Correct Answer
    A. Feels heavier when you throw it in the direction of the moving alley, and lighter when you throw it in the opposite direction.
    Explanation
    When inside a rotating space torus, the ball will experience a centrifugal force due to the rotation. This force will make the ball feel heavier when thrown in the direction of the moving alley because it adds to the gravitational force. On the other hand, when thrown in the opposite direction, the centrifugal force will subtract from the gravitational force, making the ball feel lighter. The veering of the ball to the right or left is not mentioned in the question, so it cannot be determined.

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  • 47. 

    If the Earth rotated more slowly about its axis, your apparent weight would

    • Increase.

    • Decrease.

    • Stay the same.

    • Be zero.

    Correct Answer
    A. Increase.
    Explanation
    If the Earth rotated more slowly about its axis, the centrifugal force acting on objects on the surface would decrease. This force opposes the force of gravity and contributes to the apparent weight of objects. Therefore, if the centrifugal force decreases, the apparent weight of objects would increase.

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  • 48. 

    Consider a rotating donut-shaped space habitat where living quarters are on the inside surface farthest from the axis. If the rotational speed of the habitat increases, the apparent weight of people inside

    • Increases.

    • Decreases.

    • Stays the same.

    • Is always zero.

    Correct Answer
    A. Increases.
    Explanation
    As the rotational speed of the donut-shaped space habitat increases, the centripetal force acting on the people inside also increases. This force is directed towards the axis of rotation and is responsible for the apparent weight that individuals experience. Therefore, with an increase in rotational speed, the apparent weight of people inside the habitat also increases.

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  • 49. 

    If the planet Jupiter underwent gravitational collapse, its rate of rotation about its axis would

    • Decrease.

    • Increase.

    • Stay the same.

    • more information needed

    Correct Answer
    A. Increase.
    Explanation
    When a planet undergoes gravitational collapse, its size decreases, resulting in a decrease in its moment of inertia. According to the conservation of angular momentum, when the moment of inertia decreases, the rate of rotation about the axis increases to maintain the same angular momentum. Therefore, if Jupiter underwent gravitational collapse, its rate of rotation about its axis would increase.

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Quiz Review Timeline (Updated): Apr 26, 2024 +

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  • Current Version
  • Apr 26, 2024
    Quiz Edited by
    ProProfs Editorial Team
  • Oct 15, 2012
    Quiz Created by
    Drtaylor
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