Energy and Circular Motion Exercises Quiz

Energy and Circular Motion Exercises Quiz

1. A rifle with a longer barrel can fire bullets with a larger velocity than a rifle with a shorter barrel.

a. Explain this using the impulse-momentum theorem.

b. Explain this using the work-energy theorem

2. Use physics terms to explain the benefits of crumple zones in modern cars.

3. When a gun is fired at the shooting range, the gun recoils (moves backward). Explain this using the law of conservation of momentum.

4. Rank the following in terms of increasing inertia:

A. A 10,000 kg train car at rest

B. A 100 kg person running at 5 m/s

C. A 1200 kg car going 15 m/s

D. A 15 kg meteor going at a speed of 1000 m/s

5. Rank the following in terms of increasing momentum:

A. A 10,000 kg train car at rest

B. A 100 kg person running at 5 m/s

C. A 1200 kg car going 15 m/s

D. A 15 kg meteor going at a speed of 1000 m/s

6. Rank the following in terms of increasing kinetic energy:

A. A 1200 kg car going 15 m/s

B. A 10,000 kg train car at rest

C. A 15 kg meteor going at a speed of 1000 m/s

D. A 100 kg person running at 5 m/s

7. Ben (55 kg) is standing on very slippery ice when Junior (25 kg) bumps into him. Junior was moving at a speed of 8 m/s before the collision and Ben and Junior embrace after the collision. Find the speed of Ben and Junior as they move across the ice after the collision. Give the answer in m/s. Describe the work you did to get the answer.

8. Identical marbles are released from the same height on each of the following four frictionless ramps.

Compare the speed of the marbles at the end of each ramp. Explain your reasoning.

9. A force of only 150 N can lift a 600 N sack of flour to a height of 0.50 m when using a lever as shown in the diagram below.

a. Find the work done on the sack of flour (in J).

b. Find the distance you must push with the 150 N force on the left side (in m).

c. Briefly explain the benefit of using a lever to lift a heavy object.

10. Rank the following in terms of increasing power.

A. Doing 100 J of work in 10 seconds.

B. Doing 100 J of work in 5 seconds.

C. Doing 200 J of work in 5 seconds.

D. Doing 400 J of work in 30 seconds.

11. A student lifts a 25 kg mass a vertical distance of 1.6 m in a time of 2.0 seconds.

a. Find the force needed to lift the mass (in N).

b. Find the work done by the student (in J).

c. Find the power exerted by the student (in W).

12. A satellite is put into an orbit at a distance from the center of the Earth equal to twice the distance from the center of the Earth to the surface. If the satellite had a weight at the surface of 4000 N, what is the force of gravity (weight) of the satellite when it is in its orbit? Give your answer in newtons, N.

13. Consider a satellite in a circular orbit around the Earth.

a. Why is it important to give a satellite a horizontal speed when placing it in orbit?

b. What will happen if the horizontal speed is too small?

c. What will happen if the horizontal speed is too large?

14. If you drop an object from a distance of 1 meter above the ground, where would it fall to the ground in the shortest time: Atop Mt. Everest or in New York?

15. Why do the astronauts aboard the space station appear to be weightless?

16. Why do the passengers on a high-flying airplane not appear weightless, similar to the astronauts on the space station?

17. A ranger needs to capture a monkey hanging on a tree branch. The ranger aims his dart gun directly at the monkey and fires the tranquilizer dart. However, the monkey lets go of the branch at exactly the same time as the ranger fires the dart. Will the monkey get hit or will it avoid the dart?

The remaining questions are multiple-choice questions:

18. Compared to its weight on Earth, a 5 kg object on the moon will weigh

A. the same amount.

B. less.

C. more.

19. Compared to its mass on Earth, a 5 kg object on the moon will have

A. the same mass.

B. less mass.

C. more mass.

20. The reason padded dashboards are used in cars is that they

A. look nice and feel good.

B. decrease the impulse in a collision.

C. increase the force of impact in a collision.

D. decrease the momentum of a collision.

E. increase the time of impact in a collision.

21. Suppose you are standing on a frozen lake where there is no friction between your feet and the ice. What can you do to get off the lake?

A. Bend over touching the ice in front of you and then bring you feet to your hands.

B. Walk very slowly on tiptoe.

C. Get on your hands and knees and crawl off the ice.

D. Throw something in the direction opposite to the way you want to go.

22. A car travels in a circle with constant speed. Which of the following is true?

A. The net force on the car is zero because the car is not accelerating.

B. The net force on the car is directed forward, in the direction of travel.

C. The net force on the car is directed inward, toward the center of the curve.

D. The net force on the car is directed outward, away from the center of the curve.

23. A job is done slowly, and an identical job is done quickly. Which of the following is true?

a. They require the same amount of force, but different amounts of work.

b. They require the same amount of work, but different amounts of power.

c. They require the same amounts of power, but different amounts of work.

d. They require the same amounts of work, but different amounts of energy.

24. How many joules of work are done on a box when a force of 60 N pushes it 5 m in 3 seconds?

a. 300 J

b. 12 J

c. 100 J

d. 36 J

e. 4 J

25. A 1 kg cart moving with a speed of 3 m/s collides with a 2 kg cart at rest. If the carts stick together after the collision, with what speed will they move after the collision?

a. 3 m/s

b. 1.5 m/s

c. 1 m/s

d. 2 m/s

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Important information for writing discussion questions and participation

Welcome to class

Hello class and welcome to the class and I will be your instructor for this course. This is a -week course and requires a lot of time commitment, organization, and a high level of dedication. Please use the class syllabus to guide you through all the assignments required for the course. I have also attached the classroom policies to this announcement to know your expectations for this course. Please review this document carefully and ask me any questions if you do. You could email me at any time or send me a message via the “message” icon in halo if you need to contact me. I check my email regularly, so you should get a response within 24 hours. If you have not heard from me within 24 hours and need to contact me urgently, please send a follow up text to

I strongly encourage that you do not wait until the very last minute to complete your assignments. Your assignments in weeks 4 and 5 require early planning as you would need to present a teaching plan and interview a community health provider. I advise you look at the requirements for these assignments at the beginning of the course and plan accordingly. I have posted the YouTube link that explains all the class assignments in detail. It is required that you watch this 32-minute video as the assignments from week 3 through 5 require that you follow the instructions to the letter to succeed. Failure to complete these assignments according to instructions might lead to a zero. After watching the video, please schedule a one-on-one with me to discuss your topic for your project by the second week of class. Use this link to schedule a 15-minute session. Please, call me at the time of your appointment on my number. Please note that I will NOT call you.

Please, be advised I do NOT accept any assignments by email. If you are having technical issues with uploading an assignment, contact the technical department and inform me of the issue. If you have any issues that would prevent you from getting your assignments to me by the deadline, please inform me to request a possible extension. Note that working fulltime or overtime is no excuse for late assignments. There is a 5%-point deduction for every day your assignment is late. This only applies to approved extensions. Late assignments will not be accepted.

If you think you would be needing accommodations due to any reasons, please contact the appropriate department to request accommodations.

Plagiarism is highly prohibited. Please ensure you are citing your sources correctly using APA 7th edition. All assignments including discussion posts should be formatted in APA with the appropriate spacing, font, margin, and indents. Any papers not well formatted would be returned back to you, hence, I advise you review APA formatting style. I have attached a sample paper in APA format and will also post sample discussion responses in subsequent announcements.

Your initial discussion post should be a minimum of 200 words and response posts should be a minimum of 150 words. Be advised that I grade based on quality and not necessarily the number of words you post. A minimum of TWO references should be used for your initial post. For your response post, you do not need references as personal experiences would count as response posts. If you however cite anything from the literature for your response post, it is required that you cite your reference. You should include a minimum of THREE references for papers in this course. Please note that references should be no more than 5 years old except recommended as a resource for the class. Furthermore, for each discussion board question, you need ONE initial substantive response and TWO substantive responses to either your classmates or your instructor for a total of THREE responses. There are TWO discussion questions each week, hence, you need a total minimum of SIX discussion posts for each week. I usually post a discussion question each week. You could also respond to these as it would count towards your required SIX discussion posts for the week.

I understand this is a lot of information to cover in 5 weeks, however, the Bible says in Philippians 4:13 that we can do all things through Christ that strengthens us. Even in times like this, we are encouraged by God’s word that we have that ability in us to succeed with His strength. I pray that each and every one of you receives strength for this course and life generally as we navigate through this pandemic that is shaking our world today. Relax and enjoy the course!

Hi Class,

Please read through the following information on writing a Discussion question response and participation posts.

Contact me if you have any questions.

Important information on Writing a Discussion Question

• Your response needs to be a minimum of 150 words (not including your list of references)
• There needs to be at least TWO references with ONE being a peer reviewed professional journal article.
• Include in-text citations in your response
• Do not include quotes—instead summarize and paraphrase the information
• Follow APA-7th edition
• Points will be deducted if the above is not followed

Participation –replies to your classmates or instructor

• A minimum of 6 responses per week, on at least 3 days of the week.
• Each response needs at least ONE reference with citations—best if it is a peer reviewed journal article
• Each response needs to be at least 75 words in length (does not include your list of references)
• Responses need to be substantive by bringing information to the discussion or further enhance the discussion. Responses of “I agree” or “great post” does not count for the word count.
• Follow APA 7th edition
• Points will be deducted if the above is not followed

• Remember to use and follow APA-7th edition for all weekly assignments, discussion questions, and participation points.
• Here are some helpful links
• The is a great resource