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Physics
10th -
12thgrade
Rotational Motion, Moment of Inertia and Torque
36 questions
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- 1. Multiple ChoiceIf the torque required to loosen a nut on the wheel of a car has a magnitude of 60.0 N• m, what minimum perpendicular force must be exerted by a mechanic at the end of a 45.0 cm wrench to loosen the nut?.666 Nm133.3 N66.7 N13.3 Nm
- 2. Multiple ChoiceFind the magnitude of the torque produced by a 5.0 N force applied to a door at a perpendicular distance of 65 cm from the hinge.75 Nm3.25 Nm6.3 Nm8.75 Nm
- 3. 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 at point P?
A because all the mass is close to point P
B because all the mass is far from point P
C because it has a larger radius.
D because it has less mass
- 4. Multiple Choice
A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii. If the three of them are released simultaneously at the top of an inclined plane and do not slip, which one will reach the bottom first?
cylinder because it has uniformly distributed mass.
pipe because it has a high MOI
sphere because it has a small MOI
They all reach the bottom at the same time.
- 5. Multiple Choice
The center of mass is in line with:
the exact middle of an object
the heaviest part of an object
a point at which you can balance an object
the idea that mass is evenly concentrated throughout
- 6. Multiple Choice
Stars originate as large bodies of slowly rotating gas. Because of gravity, these clumps of gas slowly decrease in size. What happens to the rotational speed of the star as it shrinks?
It rotates faster.
It rotates slower.
It starts to accelerate in the forward direction.
The rotation rate stays the same.
- 7. Multiple Choice
A seesaw with mass Z is perfectly balanced with a fulcrum in the center. If mass Z changes uniformly does the net torque change?
Yes, because the Gravitational force increases with more mass, and torque is related to Force
No, because the net torque is still zero despite increases in one of the individual components.
No, because it is balanced that means net torque is zero, a uniform increase in weight keeps it balanced keeping net torque at zero
Yes, any increase in weight will increase torque
- 8. Multiple ChoiceHow do you get the maximum torque?longer lever arm and more force at an acute angleshorter lever arm with more force perpendicularlyshorter lever arm and more force perpendicularlylonger lever arm with more force perpendicularly
- 9. Multiple ChoiceThe force of gravity on an object.massweightvolumeinertia
- 10. Multiple ChoiceTorque is the product of a force exerted on an object x distance from the force to the axis of rotation.TrueFalse
- 11. Multiple ChoiceWhen an object is experiencing a net torqueit stops.it has angular acceleration and can speed up or slow down.it must rotate.its angular momentum stays constant.
- 12. Multiple ChoiceTwo 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?the second force (at the doorknob)The two forces are equal.the first force (at the midpoint)
- 13. Multiple ChoiceAs 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?1234
- 14. Multiple ChoiceA seesaw is unbalanced with two people of different masses sitting equal distances from the center. Which of the following will result in equilibrium?The larger person moving further away from the center.Moving the smaller person closer to the center.Moving the smaller person further from the center.Making the larger person do nothing.
- 15. Multiple ChoiceThe easiest way to open a heavy door is by applying the forceNear the hingesIn the middle of the doorAt the edge of the door far from the hingesAt the top of the door
- 16. Multiple ChoiceWhat is the Unit for TorqueNmNWJ
- 17. Multiple ChoiceA construction worker is worried about applying too much torque to a bolt using his wrench. What could he do to reduce his torque on the bolt?Increase the length of the wrenchIncrease the force on wrenchReduce the length of the wrenchReduce the friction between the bolt and wrench
- 18. Multiple Choice
A balanced object with only one point of support will be:
Unstable because any applied force will cause it to tip.
Stable because the center of gravity is above the balance point
- 19. Multiple ChoiceA mouse is initially at rest on a horizontal turntable mounted on a frictionless vertical axle. If the mouse begins to walk clockwise around the perimeter, what happens to the turntable?The turntable will remain stationary.The turntable will rotate clockwise too.The turntable will rotate counterclockwise.The turntable will only move if the mass of the mouse is greater than the mass of the turntable.
- 20. Multiple ChoiceAn object will fall over if its center of gravity isoutside the object.too low.not over its area of supporttoo high.
- 21. Multiple ChoiceThe property of a body to resist change in linear motion.massweightinertiamoment of inertia
- 22. Multiple ChoiceThe property of a body to resist change in rotation.massweightinertiamoment of inertia
- 23. Multiple ChoiceA girl sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms,her moment of inertia increases and her angular speed decreases.her moment of inertia decreases and her angular speed increases.her moment of inertia increases and her angular speed increases.her moment of inertia increases and her angular speed remains the same.
- 24. Multiple ChoiceBecause the sun has several planets orbiting it, it actually wobbles as it moves through space. This happens because it center of mass changes.TrueFalse
- 25. Multiple ChoiceWhen you carry a heavy load with one arm, why do you tend to hold your free arm away from your body?To change the mass of your bodyTo be ready to grab something in case you fallTo look goodTo change the center of mass of your body and the load
- 26. Multiple ChoiceSuppose you are designing an engineless car for a downhill coasting race. What type of wheels would be the best?Solid disks.Hoops.Hollow cylinders.Diamond encrusted triangles.
- 27. Multiple ChoiceAs global warming occurs over the next century, the polar ice caps will start to melt and the water will be move from the poles to the equator. How will this change the Earth's moment of inertia?
It would increase and the day would be slightly longer.
It would decrease and the day would be slightly longer.
It would increase and the day would be slightly shorter.
It would decrease and the day would be slightly shorter.
- 28. Multiple ChoiceWhat would happen to the length of one day if Earth's moment of inertia were to increase?The day would be longer.The day would be shorter.The day would stay the same.
- 29. Multiple ChoiceA merry-go-round spins freely a 20 rpm when Diego moves quickly to the center along a radius of the merry-go-round. As he does this:the moment of inertia of the system will increase.the moment of inertia of the system will decrease.the moment of inertia of the system will stay the same
- 30. Multiple ChoiceA merry-go-round spins freely a 20 rpm when Diego moves quickly to the center along a radius of the merry-go-round. As he does this:the velocity of the merry-go-round will increase.the velocity of the merry-go-round will decrease.the velocity of the merry-go-round will stay the same
- 31. Multiple ChoiceDoes a bridge anchored resting on two pillars have any torques acting on them?No, it isn't movingYes, but they are at equilibriumYes, but it will soon break because of the torqueNo, Bridges can't have torque
- 32. Multiple ChoiceA state of equilibrium is also seen below. Each of the cars weighs the same 9800 N. Despite the fact that there is only one car on the left-hand side that is 9 m from the fulcrum, the moments balance because, the cars on the right-hand side, are ____meters from the fulcrum.4.5 m3 m1 m2 m
- 33. Multiple Choice
Where does the center of mass need to be ____ compared to the support area to keep the object balanced?
above
below
same height
none of the above
- 34. Multiple Choice
Stars originate as large bodies of slowly rotating gas. Because of gravity, these clumps of gas slowly decrease in size. What happens to the moment of inertia of the star as it shrinks?
It becomes larger.
It becomes smaller.
It stays the same because the mass stays the same.
- 35. Multiple Choice
A person holds their arms out as they walk a tightrope. How does this affect their moment of inertia.
It increases it making them easier to rotate.
It decreases it making them easier to rotate.
It increases it making them harder to rotate.
It decreases it making them easier to rotate.
- 36. Multiple Choice
As a planet orbits a star
The speed of the planet increases as it gets closer to the star.
The speed of the planet decreases as it gets closer to the star.
The speed of the planet stays constant.
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