What is Uniform circular motion: Definition and 311 Discussions

In physics, circular motion is a movement of an object along the circumference of a circle or rotation along a circular path. It can be uniform, with constant angular rate of rotation and constant speed, or non-uniform with a changing rate of rotation. The rotation around a fixed axis of a three-dimensional body involves circular motion of its parts. The equations of motion describe the movement of the center of mass of a body. In circular motion, the distance between the body and a fixed point on the surface remains the same.
Examples of circular motion include: an artificial satellite orbiting the Earth at a constant height, a ceiling fan's blades rotating around a hub, a stone which is tied to a rope and is being swung in circles, a car turning through a curve in a race track, an electron moving perpendicular to a uniform magnetic field, and a gear turning inside a mechanism.
Since the object's velocity vector is constantly changing direction, the moving object is undergoing acceleration by a centripetal force in the direction of the center of rotation. Without this acceleration, the object would move in a straight line, according to Newton's laws of motion.

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  1. S

    Help on Uniform Circular Motion Problem Please

    Homework Statement 1. Homework Statement Derive a formula for the bullet speed v in terms of D, T, and a measured angle between the position of the hole in the first disk and that of the hole in the second. If required, use \pi, not its numeric equivalent. Both of the holes lie at the...
  2. A

    Will a Box Slide on a Truck During a Sharp Turn?

    Here is the questions: A box of mass m= 10 kg is sitting on the floor of a truck as the truck rounds a curve to the left of radius 15 m at 12 m/s. There is friction between the box and the floor of the truck with mus= .45 and muk = .20. 1. Does the box slide? 2. If the box slides, in what...
  3. S

    Uniform circular motion airplane problem

    An airplane is flying in a horizontal circle at a speed of 470 km/h (Figure 6-39). If its wings are tilted 40° to the horizontal, what is the radius of the circle in which the plane is flying? Assume that the required force is provided entirely by an "aerodynamic lift" that is perpendicular to...
  4. K

    Uniform Circular Motion Tension

    Homework Statement A 100g bead is free to slide along an 80cm long piece of string ABC. The ends of the string are attached to a vertical pole at A and C, which are 40 cm apart. When the pole is rotated about its axis, AB becomes horizontal. Find the tension in the string. Find the speed...
  5. S

    More Uniform Circular Motion problems

    An Earth satellite moves in a circular orbit 605 km above the Earth's surface. The period of the motion is 96.6 min. (a) What is the speed of the satellite? a=v^2/r and T=2*pi*r/v The Attempt at a Solution So far I've tried converting my km to m and min to sec. I then tried...
  6. S

    Cross Product in Uniform Circular Motion

    Homework Statement A centripetal-acceleration addict rides in uniform circular motion with period T = 3.22 s and radius r = 3.00 m. At one instant his acceleration is a = (7.00 m/s2) i + (-9.00 m/s2) j. At that instant, what are the following values? (b) r X a The Attempt at a...
  7. C

    Uniform Circular Motion: Centripital Acceleration vs. Acceleration

    I am very new to physics and am taking a my first University Physics class. This is not a call for a problem to be solved, but a clarification on terminology. In solving problems for uniform circular motion, some problems call for the acceleration of the object (a=v^2/r) and others the...
  8. E

    Uniform circular motion with unknown mass

    Homework Statement A satellite is in a circular orbit around an unknown planet. The satellite has a speed of 1.7x10^4 m/s and the radius is 5.25x10^6 meters. A second satellite also has a circular orbit around the same planet and has an orbit radius of 8.6x10^6 meters. What is the orbital...
  9. B

    Uniform Circular Motion Displacement

    In uniform circular motion: True False Displacement is constant. True False Velocity is constant. True False Acceleration and velocity are perpendicular. True False Speed is constant. True False Accleration direction is constant. True False Acceleration magnitude is constant...
  10. H

    Uniform Circular Motion -Explanatory questions

    Homework Statement A coin is placed on a turntable. When the motor is stated the turntable starts to rotate. Before it reaches full rotational speed the coin flies off. Explain why and in what direction will it go? And A pilot of an aeroplane, when pulling out of a steep dive can...
  11. I

    Rock hanging from ceiling swinging uniform circular motion

    Homework Statement A rock of mass 5.5kg is hanging from the ceiling moving in uniform circular motion. The radius of the orbit is .8m. The angle of the rope in comparison to if it were hanging straight down is 15 degrees outward. What is the magnitude of the force of the cord on the...
  12. B

    Uniform Circular Motion Question

    1. Homework Statement : A body of mass 81.7g is moving in a circular path of radius 0.65m. If we calculate the centrifugal force on it to have a magnitude of 0.35N, what is the period of revolution? (2 decimals, UNITS!)(p = 3.14) 2. Homework Equations : I'm given the following equations...
  13. D

    Uniform Circular Motion of a train

    I was wondering if someone could help me figure out what formulas to use solving this problem. My professor gave me the answer (as a way to check our answers) : 1.48 m/s^2 inward and 29.9 degrees backward The problem is: A train slows down as it rounds a sharp horizontal turn slowing from...
  14. F

    What Is the Minimum Speed for Tether Ball Stability?

    A 0.75kg tether ball is attached to a 1.6m massless string. What is the minimum speed needed to keep the ball at a radius of 1.2m? If the radius was replaced with a string of the same length what would be the tension of each string if the ball's speed is 5.5m/s? For part 1 I think the...
  15. O

    Problem - Newton's second law applied to uniform circular motion

    Here is the problem I am working on: http://img45.imageshack.us/img45/5566/image0002bv6.jpg Here is my work: http://img177.imageshack.us/img177/7127/image0001zy6.jpg I cannot solve (2) for v since there are no real roots. When I set up the net forces in the x-direction in (1), should I...
  16. mbrmbrg

    How Does Centripetal Acceleration Affect an Astronaut's Motion in a Centrifuge?

    An astronaut is rotated in a horizontal centrifuge at a radius of 3.0 m. (a) What is the astronaut's speed if the centripetal acceleration is 8.0g? (b) How many revolutions per minute are required to produce this acceleration? (c) What is the period of the motion? I got the question...
  17. H

    Just need a confirmation (Force in uniform circular motion)

    I'm a little unsure with my some of my answers here, mainly because it seems too simple. The Questions ask: A race car driver is driving her car at the record breaking speed of 225 km/h. The first turn on the course is banked at 15 degrees, and the car's mass is 1450 kg. a) Calculate the...
  18. W

    Uniform Circular Motion - Find Force

    Hello, The first part of the problem confuses me, but I have solved the second part. "In the Bohr model of the hydrogen atom, the speed of the electron is approximately 2.20 x 10^6 m/s. Find (a) the force acting on the electron as it revolves in a circular orbit of radius 0.530 x 10^-10 m...
  19. N

    Uniform Circular Motion & Gravity: A Connection?

    Is it just me, or is there a huge connection between Uniform Circular Motion and Gravity? A body of mass caught in uniform circular motion exerts a constant centripetal accelerating force, does it not? I don't know if it's just me, but that sounds like the exact description of gravity. So, I...
  20. M

    Uniform Circular Motion of centrifuge

    Hi there. I need some help with this question. Can anyone help me... A centrifuge is a device in which a small container of material is rotated at a high speed on a circular path. Suppose the centripetal acceleration of the sample is 6.25 X 103 times as large as the acceleration due to...
  21. D

    Uniform Circular Motion frequency

    Yesterday I did a lab with the purpose of determining the relationship between the frequency of revolution of an object in uniform circular motion and 1)the magnitude of the force (causing the circular motion) 2)the radius of the circular path 3)the mass of the object. Well by graphing my...
  22. Z

    Uniform circular motion and Ferris wheel

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  23. S

    Uniform circular motion; radial and lateral components?

    Hello, I'm trying to understand circular motion more intimately. Let's say I have a 1.8 m long piece of twine that I attach to my ceiling and attach a rock with a mass of 650 g from the hanging end. Let's say (with my superhuman coordination) I manage to get the rock spinning in a perfectly...
  24. N

    Maximizing Angular Frequency for Stable Uniform Circular Motion with Two Blocks

    here is the problem: --- Two identical blocks are tied together with a string and placed along the same radius of a turntable that is spinning about its center. The inner block is 1 cm from the center and the outer block is 6 cm from the center. The coefficient of static friction between the...
  25. A

    Question qbout uniform circular motion

    A particle is performing uniform circular motion.If the angular displacement is finite then whether angular velocity is a vector quantity or not?abhijitlohiya@gmail.com
  26. E

    Help IN UNIFORM CIRCULAR MOTION

    A 1kg mass is attached to a cord 1 meter long and made to move as a conical pendulum. If the cord makes 30 degrees with the vertical, find a.) the tension in the cord; b.) the period of the motion and c.) the speed of the mass...
  27. E

    How can we solve a conical pendulum using principles of physics?

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  28. S

    Uniform Circular Motion with friction

    A car drives around a horizontal curve with a frictional coefficient of 0.58. What is the maximum safe speed for the carif the radius of the turn is 125m? r= 125m uk= 0.58 v=? ok I set up the problem as Fc=Ff-Fg m (v2/r)=ukFn-(m)(g) so the masses would cancel, but I'm stuck and...
  29. N

    Non uniform circular motion and friction

    A car is at rest in a circle of radius r. The car then accelerates, but friction limits the speed to some max speed v. At what angle is the max speed v reached? (calculus is involved). The key is to draw a detailed FBD, which I need help with. So far the forces I have are: centripital...
  30. H

    Uniform circular motion (I DON'T KNOW)

    WHAT IS THE MAXIMUM SPEED WITH WHICH A 1050KG CAR CAN ROUND A TURN OF RADIUS 77M ON A FLAT ROAD IF THE COESFFIECENT OF STATIC FRICTION BETWEEN TIRES AND ROAD IS .80? here is what I have so far? m= 1050kg r =77m uk =.080 FN=mg FR =ukfn (1050kg)(9.8m/s) = FN = 10290N (.80) (10290) =...
  31. N

    Non uniform circular motion and friction

    What are the Forces of a car that is accelerating around a circle? There is friction between the road and the car. Centripital force(in towards the circle) Static Friction(in towards the circle) However there is also another component of friction that I am missing? Any ideas? Thanks
  32. L

    Uniform Circular Motion questions

    1. A .25kg mass attached to a string of length 1m is spun in a horizontal circle. At what speed must it travel so that the angle the string makes with the horizontal is 30 degrees? 2. A block of mass m slides around a circular path in a conic surface with vertex angle 2theta. Determine the...
  33. S

    Uniform Circular Motion of streetcar

    An old streetcar rounds a flat corner of radius = 9.1m at 4.444 m/s. What angle with the vertical will be made by the loosely hanging hand straps. I don't really know what I am looking for, Can anyone Help?
  34. W

    Uniform Circular Motion Around an Oval: Understanding Acceleration Vectors

    I understand Uniform Circular Motion and an object's acceleration while in UCM. But, how does that change when an object moves around an oval? Does the acceleration vector point more towards the line tangent to the oval than just to the center? What if the object itself has increasing or...
  35. N

    Uniform Circular Motion roller coaster

    This is another problem a buddy of mine and I cannot figure out if our life depended on it. Here's the question word for word: A roller coaster track has a hill with a circular curve of radius 20 m. Find the speed of the roller coaster at the top of this hill. Started by drawing a picture...
  36. T

    Calculating Radius for Stone in Rotating Tire with Static Friction

    please help...uniform circular motion..I am STUMPED:frown: A stone has a mass of 3.0 10-3 kg and is wedged into the tread of an automobile tire, as the drawing shows. The coefficient of static friction between the stone and each side of the tread channel is 0.71. When the tire surface is...
  37. S

    Uniform Circular Motion of a particle

    Im new at physics and have been looking at this question all day, any help would be greatly appreciated, here it is A particle moves along a cirular path over a horizontal xy coordinate system, at constant speed. At time t1 = 4.00s, it is at point (5.oom, 6.00m) with velocity (3.00 m/s)j...
  38. M

    Uniform Circular Motion questions

    The drawing shows a baggage carousel at an airport. Your suitcase has not slid all the way down the slope and is going around at a constant speed on a circle (r = 11.0 m) as the carousel turns. The coefficient of static friction between the suitcase and the carousel is 0.910, and the angle in...
  39. B

    Uniform circular motion and velocity vector

    hi Object in uniform circular motion is moving around the perimeter of the circle with a constant speed and while the speed of the object is constant, its velocity is changing . The direction is always directed tangent to the circle To my question . Velocity vector at particular point A...
  40. D

    Uniform circular motion - centripetal force and banked curves

    well first off, here's the problem: A car can negotiate an unbanked curve safely at a certain maximum speed when the coefficient of static friction between the tires and the ground is 0.997. At what angle should the same curve be banked for the car to negotiate the curve safely at the same...
  41. D

    Uniform Circular Motion equations

    Greetings! I'm looking for some help, so here is my predicament: In my Physics class we did a lab in which we found two relationships involved with the velocity of an object in uniform circular motion. The relationships were that velocity squared is proportional to not only mass, but...
  42. M

    Uniform circular motion proportionalities

    I have a lab with which I am having some major difficulties. (a) Whats the relationship between frequency of revolution and - the magnitude of the force causing the circular motion(centripetal force)? - the radius of the circular path? - the mass of the object? (b)...
  43. M

    Uniform circular motion proportionalities

    I have a lab with which I am having some major difficulties. (a) Whats the relationship between frequency of revolution and - the magnitude of the force causing the circular motion(centripetal force)? - the radius of the circular path? - the mass of the object? (b)...
  44. G

    Uniform Circular Motion Confusion

    I have a question about uniform circular motion that is just confusing me. Maybe one of you can elucidate it for me. Say I am in a roller coaster car and I am traveling in a loop. At the top of the loop if my velocity is not great enough I should fall out of the loop but because the car is...
  45. M

    Velocity in uniform circular motion

    A 300-m tall tower is built on the equator. How much faster does a point at the top of the tower move than a point at the bottom?
  46. V

    Uniform Circular Motion: Understanding Forces in Space | Basic Physics Question

    What i am going to write is an extremely basic question. It's not a paradox. But why I thought of writing it here, is because meny people go wrong in answering it. Let's see how many of you go wrong here. OK, the question is as simple as this :- You are in space surrounded by an isotropic...
  47. J

    Uniform Circular Motion of a ball

    i'm having trouble in solving this problem. I've tried several ways to solve this problem but still have not come up with the correct solution. the question is: A ball on the end of a string is revolved at a uniform rate in a verticle circle of radius 65 cm. If its speed is 4.25 m/s and its...
  48. A

    Please help with a uniform circular motion problem

    Hey can you guys give me some help with this physics problem.. having real issues figuring it out, and I've looked all over the internet. Google'd like 100 times... A Particle at Constant Speed A particle P travels with constant speed on a circle of radius r = 3.35 m (Figure 5-39) and...
  49. U

    Uniform Circular Motion problem

    there's a 150 lb person on a rolling chair and moves in a circle when a motor with a rope attached on it is hooked up to the chair. If the radius of the circle is 7 ft, how much horsepower would the motor need to have to move the person at 1 m/s given that the friction coefficent is about...
  50. A

    About the uniform circular motion

    Hi.. I have problem solving this question.. if anyone could help me out, i would really appreciate it. Q. Taking the Earth to be a sphere of radius 6380 km, rotating about its own axis once every 24 hours, find the speed of rotation at the Equator. What is the apparent weight of a person...
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