Download Circular Motion Web Quest

Circular Motion Web Quest:
Access the Web site listed below. Answer all questions completely and draw diagrams to aid explanations
when applicable.
http://www.physicsclassroom.com/Class/circles/index.cfm
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?
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9. Which vector below represents the direction of the velocity vector
when the object is located at point B on the circle?
10. Which vector below represents the direction of the acceleration
vector when the object is located at point C on the circle?
11. Which vector below represents the direction of the velocity vector when the object is located at point C
on the circle?
12. Which vector below represents the direction of the acceleration vector when the object is located at
point A on the circle?
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?
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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.
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Circular Motion Web Quest:
Access the Web site listed below. Answer all questions completely and draw diagrams to aid explanations
when applicable.
http://www.physicsclassroom.com/Class/circles/index.cfm
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.
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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:
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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).
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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.
b.
c.
d.
a=?
Fg=?
Fn=?
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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