Reading Quiz #9 (2024)

Question 1:

What is a "feeling of acceleration"? How does it relate to acceleration?

Answer:

The book discusses this near the bottom of p. 99. Because of inertia, when you accelerate in a particular direction, you have the sensation of a force acting on you in the opposite direction. Your book calls this sensation the feeling of acceleration, which will always point in the opposite direction of the the actual acceleration (and actual net force). The strength of the feeling of acceleration will be proportional to the actual acceleration.

1. A "feeling of acceleration" is the weightlike sensation in the direction directly opposite the direction of acceleration. The amount of this feeling of acceleration is proportional to the amount of the acceleration.
2. A "feeling of acceleration" is the backward feeling you experience as you accelerate forward. This is an apparent force, meaning it is not due to a real force, but is the result of inertia. This apparent force points in the direction opposite the acceleration that caused it, and its strength is proportional to the acceleration that caused it.
3. A feeling of acceleration is the heavy feeling you experience as you accelerate. It is actually the result of intertia. This feeling of acceleration always points opposite the direction of acceleration and is proportional to the force of acceleration.
4. The feeling of acceleration is the feeling that your accelerating the opposite direction that you are actually accelerating.
5. A feeling of acceleration is the apparent or ficticious force that you feel when you are acellerating. It is caused by your surroundings exerting force on you to accelerate, like when the seat of the roller coaster pushes on your back to move your body forward. You feel like you are being pushed backwards, in the opposite direction of the acceleration, but really it's just the slow chain reaction of forces to move each part of your body forward.
6. a feeling of acceleration is a fictitious force that results from acceleration. It is opposite from the direction of acceleration and has proportional strength to that acceleration. So if you are accelerating forward you will feel a backwards force upon you.
7. A "feeling of acceleration" is the backward heavy feeling in your gut as you accelerate forward in the result of intertia and is not due to a real backward force. It relates to acceleration because you get the "feeling of acceleration" when you accelerate.
8. A "feeling of acceleration" is the heavy feeling in your gut that you feel when you accelerate forward. While this feeling does occur during acceleration, the feeling is due to inertia, not a backward force. This "feeling of accekeration" is equal in strength and opposite in direction to the acceleration that causes it.
9. A feeling of acceleration is due to your body's inertia and acts in the opposite direction of your actual acceleration because you are resisting the acceleration.
10. A feeling of accleration is the heavy feeling you get when then object you're in accelerates. It is the opposite direction of acceleration and is porprtinal to the strength of acceleration.
11. The feeling inertia gives you when you accelerate in a direction. It points in the opposite direction of the actual acceleration and its the same strength as the acceleration.
12. The feeling you get from inertia when somethiing accelerates, such as feeling pressed back into your seat when your car accelerates quickly
13. The "feeling of acceleration" is when your body feels like it is being pushed in the opposite direction as the way you are acclerated. It is related to acceleration becasue it is a feeling that is the result of being accelerated.
14. The feeling is your body's intertia trying to remain at its current velocity. It relates to acceleration because they are essentially opposing forces.
15. A feeling of acceleration is the weightlike sensation you experience as you accelerate. A feeling of acceleration relates to acceleration because it always points in the direction opposite the acceleration that causes it, and its strength is proportional to that acceleration.
16. A feeling of acceleration is what the object being accelerated feels as a result of inertia. The feeling is opposite to that of the actual direction of acceleration. For example, a person sitting in a car accelerating forward will experience a backwards "feeling of acceleration" as their body's inertia tries to keep their body in its current position while the car tries to accelerate it forward.
17. It is the backward heavy feeling you get in your gut when you accelerate forward; it is the result of your inertia and is not due to a real backward force. It always points in the direction opposite the acceleration that causes it and its strength is proportional to that acceleration.
18. A feeling of acceleration is a heavy backward feeling in your gut that is opposite of the acceleration that causes it; its strength is proportional to that acceleration.
19. The feeling of acceleration is the feeling of a backward force as you accelerate forward. As your car accelerates forward, the backward sensation you feel is caused by your body's inertia, not a real backward force like it might feel. This feeling is jsut as strong as the acceleration causing it, but it points in the opposite direction of the acceleration.
20. This is when someone feels a heavy feeling in his/her stomach as you accelerate forward. It relates to acceleration because, as you accelerate forward, the force always points in the direction opposite the acceleration that causes it. Its strength is also proportional to that acceleration.
21. Feeling of acceleration is the combination of the feeling in your gut from the acceleration you are experiencing, which is always in the opposite direction of the acceleration; and also the downward pull of gravity which form a feeling of a heavy weight/
22. Gravity has not stopped working. If you accelerate downward at just the right rate, the upward feeling of acceleration will exactly cancel your downwarwd weight. The roller coaster will no longer be supporting you and you will be accelerating at 9.8 m/s2.
23. A Feeling of acceleration is a person undergoing acceleration experiences a weightlike sensation in the direction exactly opposite the direction of acceleration. The amount of this feeling of acceleration is proportional to the amount of the acceleration.

Question 2:

(Chapter 3, Exercise 38, p. 110) People falling from a high diving board feel weightless. Has gravity stopped exerting a force on them? If not, why don't they feel it?

Answer:

The diver still has mass and is still near the surface of the earth, so they do still have the force of gravity acting on them. However, they feel weightless because their apparant weight is zero. The diver's weight points down; the diver's feeling of acceleration points up; and the diver's apparant weight is the combined feeling of the weight and the feeling of acceleration.

1. Gravity has not stopped exerting a force on the divers. The divers feel weightless because they are falling from the board at an acceleration equal to gravity and there are no forces to oppose gravity. We feel weight in relation to the forces that oppose gravity.
2. Gravity has not stopped exerting a force on the diver, but during free fall your apparent weight is zero. A diver feels weightless because as he falls at 9.8m/s2, his upward feeling of acceleration is the same strength (9.8 m/s2) but directed upward. Therefore the two cancel each other, making the diver feel weightless.
3. Gravity has not stopped exerting a force on them. They don't feel gravity becuase they are accelerating downward at such a rate that the upward feeling of acceleration will cancel the feeling of your weight, so you feel weightless.
4. Gravity is still present, but inertia keeps the person from rapidly falling downward.
5. No, gravity is still exerting the same force on them. Since there is no force acting on them to counteract gravity, they don't feel the sensation of weight that results from a support force. Instead, they just feel weightless because they are moving in sync with gravity.
6. When a diver freefalls, his acceleration downward creates a feeling of acceleration upward that matches the downward wieght. This causes the apparent wieght to be zero and the diver to feel wieghtless.
7. Gravity has not stopped exerting a force on them Instead, the divers are in free fall so they are accelerating downward at the full acceleration due to gravity. The upward feeling of acceleration matches their downward weight so their apparent weight is zero. Thus they feel weightless.
8. Gravity hasn't stopped exerting a force on them; however, they don't feel the force of gravity as they are falling because they are experiencing a feeling of acceleration that is stronger than their weight.
9. The diver's downward acceleration creates an upward "feeling of acceleration." Gravity has not stopped exerting a force on the diver. Rather, in combination with the diver's weight (due to gravity), the diver experiences a feeling of weightlessness.
10. Gravity is still exerting a force on them, but the upward feeling of acceleration will cancel the downward weight if the acceleration is at the right rate.
11. Gravity has not stopped working on them, but there is no force to cancel out any of gravity's effect, so you feel weightless. The absence of a force to cancel out gravity causes a person to feel like gravity is not acting upon them.
12. Gravity is still working on the diver. However, your apparent weight is zero. your upward acceleration is equal to that of your weight, so they cancel out and you feel weightless.
13. People falling from a high diving board feel weightless because
14. Gravity is still exerting a force, but because there is no ground holding you up, your body parts dont have to hold one another up, and so you don't feel as much force as normal and you think you feel weightless.
15. People falling from a high diving board feel weightless because as a person falls from a high dive they r accelerating downward, and that combined with thier weight leaves the person with a feeling of weightlessness, but gravity has not stopped exerting a force on them.
16. Gravity is still exerting its force, but people feel weightless because the weight they normally feel is gravity pushing down on them. When they are free-falling, that force is pushing them down and they do not need to oppose it.
17. No, gravity has not stopped exerting a force on them, it's just that there is no upward force acting on them to counteract the force of gravity. Therefore, they feel as if they are free-falling because the only force that is making them accelerate is gravity.
18. Gravity continues to exert a force, but your internal support forces are absent and nothing is pushing back on you besides air resistance.
19. No gravity has not stopped exerting a force on them. The diver does not feel the force of gravity because he feels an oppositely directed "feeling of acceleration." This feeling combined with his downward weight gives him a small apparent weight, and thus the feeling of weightlessness.
20. This is because when people fall, they eventually reach a point where the upward acceleration equals their downward weight, and they cancel eachother out. The person eventually not be accelerating anymore. A free falling object is only subject to forces of gravity. In order for people to feel upward acceleration and their weight pulling them downward, you have to continue to accelerate, and the only way to do that is to either speed up, slow down, or change direction.
21. Gravity has not stopped exerting a force, instead the upward pointing "feeling of acceleration" works to cancel out our feeling of the downward acceleration of gravity.
22. Your acceleration is downward, toward the center of the circle.
23. No gravity has not stopped exerting a force on them. They feel weightless because their feeling of acceleration and their actual acceleration are equal to each other but are in opposite directions.

Question 3:

(Chapter 3, Exercise 42, p. 110) As your car reaches the top in a smoothly turning Ferris wheel, which way are you accelerating? (If you don't know, a Ferris wheel makes a vertical circle, and "smoothly turning" means uniform circular motion in this case).

Answer:

The acceleration in uniform circular motion points towards the center of the circle. When the car is at the top of the Ferris wheel, towards the center of the circle means down.

1. You are accelerating directly toward the center of the Ferris wheel, due to centripetal force.
2. At the top of a smoothly turning Ferris wheel your car is accelerating toward the center of the circle, so you experience a feeling of acceleration directed outward, which at this point means directly upward. Since your weight is downward and your feeling of acceleration upward, your apparent weight is actually upward which explains why you feel as though you are being lifted off your seat.
3. You are accelerating towards the center of the ferris wheel.
4. The person is accelerating forward with a feeling of acceleration the opposite direction.
5. You are always accelerating toward the center of the ferris wheel, because this is the centripital force that keeps you moving in a circle. So, the acceleration at the top of the ferris wheel is straight down.
6. You are accelerating inward, since the ferris wheel is circular and you experience centripetal force.
7. You are accelerating down, or into the center of the Ferris wheel.
8. You are always accelerating toward the center of the circle/the pivot, so in this case, I think you are accelerating down.
9. As the Ferris wheel reaches the top, you are accelerating downwards because you are always accelerating in towards the pivot (otherwise you'd go flying off).
10. You are accelerating downward towards the center of the Ferris wheel.
11. You are accelerating up.
12. You are accelerating downward, but the ferris wheel keeps you moving in a circular direction
13. You are accelerating downward, because you were traveling up, and at the top you come to a stop (vertically). Therefore you would be acclerating down.
14. As you reach the top, you are decelerating upwards and are accelerating towards the direction of the central pivot.
15. As your car reaches the top in a smoothly turning ferris wheel, you are accelerating upward.
16. Your acceleration is downwards, toward the center of the Ferris wheel. This is due to gravity and centripetal force.
17. I guess if this is uniform circular motion that would mean that even though the car would naturally want to continue on its straight line path due to inertia, it is being pulled in by the ferris wheel and so the car would constantly be accelerating toward the center of the circular ferris wheel.
18. You are accelerating towards the center of the ferris wheel.
19. You are accelerating toward the center of the circle: at the top of the Ferris wheel, this would be straight downward. The centripetal force of the Ferris wheel pushes you toward the center, so you experience centripetal acceleration and always accelerate toward the center.
20. I think you are accelerating toward the center of the circle, so in this case, your acceleration would be downward.
21. You are accelerating inward and downward. (I'm assuming here that the same forces as outlined by 3.3.7 also apply to a ferris wheel.
22. none
23. At the top of the ferris wheel you are accelerating towards the center of the wheel, because your acceleration is perpendicular to your velocity.

Question 4:

What concepts or equations from the reading did you find confusing? What would you like us to spend class time discussing further?

Answer:

Your responses below.

1. centripetal versus centrifugal force.
2. I understood everything from this reading.
3. I was confused by the section discussing the actual forces on a roller coaster compared to the forces you feel while riding it.
4. im a bit confused on the direction of acceleration for some of the examples.
5. Can't think of anything...
6. i found some of the stuff about apparent wieght confusing.
7. I still don't understand the concept of weightlessness and why it happens.
8. See question 3; I'm not positive about my answer.
9. roller coaster acceleration
10. I find it hard to understand how your apparent weight can point upward.
13. I think I understand all of the concepts in this reading.
14. NA
15. I had a lot of trouble understanding a lot of concepts in this chapter. I was confused about the concepts of rollar coasters and how they work, and how accelertation changes. I also had trouble understanding how you can have a "feeling of acceleration."
16. --
17. I was a little confused with the Check Your Figures #1 problem on page 102 called "Going for a Spin."
18. None :)
19. I was confused by the discussion of measuring the feeling of acceleration as "1 gravity" or "1 g."
20. The part about acceleration when there is more than one car on the roller coaster.
21. I wasn't struggling with anything in this reading.
22. none
23. Basically a review of everything would be helpful.

Question 5:

What material from previous classes are you still having difficulty with?

Answer:

Your responses below.

1. i'm okay with past material, thanks.
2. I'm okay with the material we've covered so far.
3. Nothing.
4. nothing at this time.
6. i think i am pretty caught up
7. Everything is pretty clear right now.
8. None.
9. spring constants
10. nothing
13. I understand most of the concepts we have covered in previous classes.
14. On HW3, the explaination part of where the energy came from in problem 19 confused me a little.
15. I think i understand most of the material we have discussed so far.
16. --
17. I think I understand everything so far.
18. None
19. From section 3.2, I am a little confused about collision and rebound energy.
20. I'm still having difficulty with angular acceleration and torque, like problem #17 on the homework.
21. I had a few issues with the HW, but figured them out.
22. The spring questions for hw were difficult espcieally hw question 20.