Circular Motion Web Quest: - wsfcs.k12.nc.us



Circular Motion Web Quest:

Access the Web site listed below. Answer all questions completely and draw diagrams to aid explanations when applicable.



Lesson 1: Motion Characteristics for Circular Motion

Speed & Velocity

1. What does the phrase Uniform Circular Motion suggest? Give an example other than the car example used in the web site.

2. Average speed is calculated by dividing distance by time. How is the speed of an object moving in uniform circular motion calculated?

3. This semester we have used “t” to represent time in equations. What does “T” represent? Explain what T signifies.

4. Do objects moving in uniform circular motion have constant speed? Constant velocity? Explain.

5. What term is used to describe the direction of a velocity vector? Why is this term used?

Acceleration

6. Is an object moving in uniform circular motion accelerating? Explain.

7. Objects moving in circles at a constant speed accelerate towards the ___________ of the circle.

8. What is an accelerometer?

9. Which vector below represents the direction of the velocity vector

when the object is located at point B on the circle?

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10. Which vector below represents the direction of the acceleration vector when the object is located at point C on the circle?

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11. Which vector below represents the direction of the velocity vector when the object is located at point C on the circle?

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12. Which vector below represents the direction of the acceleration vector when the object is located at point A on the circle?

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Centripetal Force

13. What is centripetal force? What does the term centripetal mean?

14. Why, when sitting as a passenger in a car that is making a circle (turn) to the left do you feel as if there is an outward acceleration or force when there really is an inward acceleration?

Centrifugal Force

15. What does centrifugal mean?

16. Why is there so much misconception regarding centrifugal forces?

17. Does the sensation of being thrown outward from the center of a circle mean that there was definitely an outward force?

18. Click on the first animation button. Describe what is happening. Then do the same with the second animation button.

Circular Motion Mathematics

19. List below all equations in red.

Read through the practice problems and then draw diagrams and show all steps as you answer the following questions:

20. A Lincoln Continental and a Yugo are making a turn. The Lincoln is four times more massive than the Yugo. If they make the turn at the same speed, then how do the centripetal forces acting upon the two cars compare. Explain.

21. The Cajun Cliffhanger at Great America is a ride in which occupants line the perimeter of a cylinder and spin in a circle at a high rate of turning. When the cylinder begins spinning very rapidly, the floor is removed from under the riders' feet. What affect does a doubling in speed have upon the centripetal force? Explain.

22. Determine the centripetal force acting upon a 40-kg child who makes 10 revolutions around the Cliffhanger in 29.3 seconds. The radius of the barrel is 2.90 meters.

Circular Motion Web Quest:

Access the Web site listed below. Answer all questions completely and draw diagrams to aid explanations when applicable.



Lesson 2: Applications of Circular Motion

Newton’s Second Law

1. Explain how Newton’s Second Law of Motion can be used to analyze the circular motion as shown in the photos below:

Read through the practice problems and then draw diagrams and show all steps as you answer the following questions:

2. A 1.50-kg bucket of water is tied by a rope and whirled in a circle with a radius of 1.00 m. At the top of the circular loop, the speed of the bucket is 4.00 m/s. Determine the acceleration, the net force and the individual force values when the bucket is at the top of the circular loop.

3. A 1.50-kg bucket of water is tied by a rope and whirled in a circle with a radius of 1.00 m. At the bottom of the circular loop, the speed of the bucket is 6.00 m/s. Determine the acceleration, the net force and the individual force values when the bucket is at the bottom of the circular loop.

Roller Coasters

4. Explain why is the thrill of a roller coaster due to the acceleration rather than the speed.

5. Draw individual diagrams to show the acceleration at points A, B, C & D of the diagram to the right:

6. An inward acceleration is caused by an __________ net force.

7. If friction and air resistance are ignored, what two forces will be experienced by a roller coaster car, or occupant?

8. Gravity always acts________ and the normal force always acts _______ to the track.

9. Why will the rider on a roller coaster feel heavier at the bottom of a loop and lighter at the top of a loop?

10. Is it possible to experience free fall on a roller coaster? Explain.

Read through the practice problems and then draw diagrams and show all steps as you answer the following question:

11. Noah Formula is riding an old-fashioned roller coaster. Noah encounters a small hill having a radius of curvature of 12.0 m. At the crest of the hill, Noah is lifted off his seat and held in the car by the safety bar. If Noah is traveling with a speed of 14.0 m/s, then use Newton's second law to determine the force applied by the safety bar upon Noah's 80-kg body.

Athletics

12. What is the most common example of the physics of circular motion in sports?

13. Does the motion of an athlete have to be a full circle to be considered circular motion? Explain.

14. For the speed skater depicted in the picture to the right, draw Free Body Diagrams showing the two components of the contact force.

15. Explain the interactions that occur between a skater and the ice that enable a skater to move across the ice as they do.

16. A turn is only possible when there is a component of force directed towards the ______ of the circle about which the person is moving.

17. Any given physical situation can be analyzed in terms of the individual _____ which are acting upon an object; these individual forces must add up to the _____ force.

18. Read the “Suggested Method of Solving Circular Motion Problems” and write the steps in your own words (paraphrase).

Read through the practice problems and then draw diagrams and show all steps as you answer the following questions:

19. A 55.0-kg softball player runs at 7.0 m/s around a curve whose radius is 15.0 m. The contact force (vector combination of the frictional force and the normal force) acting between the ground and the player's feet supply both the centripetal force for making the turn and the upward force for balancing the player's weight. Use a free-body diagram and your understanding of circular motion and Newton's second law to determine:

a. a=?

b. Fg=?

c. Fn=?

d. Ff=?

20. In the hammer throw, a sphere is whirled around in a circular path on the end of a chain. After revolving about five times the thrower releases his grip on the chain and the "hammer" is launched at an angle to the horizontal. A diagram of the athlete and the hammer is shown to the right. Assume that the hammer is moving in a circle in a horizontal plane with a speed of 27.0 m/s. Assume that the hammer has a mass of 7.30-kg and that it moves in a circle with a 1.25-m radius. Since the hammer is moving in a horizontal plane, the centripetal force is directed horizontally. The vertical component of the tension in the chain (directed upward) is balanced by the weight of the hammer (directed downward). Use the diagram and an understanding of vector components to determine the tension in the chain.

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