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. G

    Ball Suspended from Ceiling (Uniform Circular Motion)

    Homework Statement A ball of mass M = 0.5kg is suspended from a string whose other end is attached to the ceiling. The ball travels in a horizontal circle of radius R = 1.5m at a constant speed of v = 2 m/s...
  2. G

    Airplane Pilot, dealing with Uniform Circular Motion

    Homework Statement A 78.4-kg airplane pilot pulls out of a dive by following, at a constant speed of 162 km/h, the arc of a circle whose radius is 321.0 m. At the bottom of the circle, he is accelerating at 6.31 m/s upwards. What is the force exerted on the pilot by the airplane seat...
  3. K

    Dynamics of Uniform Circular Motion Quesiotn

    Homework Statement A satellite has a mass of 5700 kg and is in a circular orbit 4.2 multiplied by 10^5 m above the surface of a planet. The period of the orbit is two hours. The radius of the planet is 4.25 multiplied by 10^6 m. What is the true weight of the satellite when it is at rest on...
  4. G

    Uniform Circular Motion Problem

    Homework Statement A circular curve of highway is designed for traffic moving at 93 km/h. Assume the traffic consists of cars without negative lift. (a) If the radius of the curve is 210 m, what is the correct angle of banking of the road? (b) If the curve were not banked, what would be the...
  5. P

    Uniform Circular Motion Hills and Cars

    1a. Homework Statement You are riding in a car over a hill that has a radius of curvature R. What speed should you be going if you want to feel one-third of your normal weight. Express your answer in terms of the radius R and the acceleration due to gravity g. 1b. You continue your...
  6. G

    Uniform circular Motion Problem

    Homework Statement A particle moves along a circular path over a horizontal xy coordinate system, at constant speed. At time t1 = 3.80 s, it is at point (5.10 m, 5.60 m) with velocity (3.30 m/s) and acceleration in the positive x direction. At time t2 = 10.0 s, it has velocity (–3.30 m/s) and...
  7. M

    Uniform Circular Motion: Speed of the bullet

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  8. W

    Uniform Circular Motion for particle of mass

    Homework Statement A particle of mass m=1kg moves counterclockwise in a horizontal circle of radius r=1m with uniform speed of 1 m/s. Determine the velocity, acceleration, total force and the component of the the total force on the particle in direction of its velocity as a function of the...
  9. J

    Uniform circular motion - calculating force of tension

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

    Dynamics of Uniform Circular Motion

    Homework Statement A suitcase is on a sloped carousel (slope = 36degrees) with a radius of 11m and a constant speed. The suitcase has not slid all the way down the carousel.The coefficient of static friction between the suitcase and the carousel is 0.76. How much time is required for the...
  11. D

    Reference frame for uniform circular motion

    Hi. Say a particle is moving around in uniform circular motion. The way my book attacks this problem is by placing the coordinate system such that one axis is in the radial direction and the other axis is in the tangential direction. Then we have the following for the radial acceleration...
  12. T

    Uniform circular motion - frequency vs. centripetal force.

    I need to find a relationship between the centripetal force and frequency of horizontal circular motion, and then find the theoretical gradient of the graph between log(frequency) vs. log(centripetal force). The radius of the string used was constant at 60cm. I think that f = k^Fc where k is...
  13. D

    Identifying the forces acting on masses in uniform circular motion.

    Homework Statement Two particles of masses 2kg and 1kg are attached to a light string at distances 0.5m and 1m respectively from one fixed end. Given that the string rotates in a horizontal plane at 5 revolutions/second, find the tensions in both portions of the string. Homework Equations...
  14. U

    What is the derivation of the centripetal acceleration in terms of position?

    This problem has been discussed before, but one of the parts were not discussed. Homework Statement Your calculation is actually a derivation of the centripetal acceleration. To see this, express the acceleration of the particle in terms of its position r(t). r(t) = Rcos(\omega...
  15. O

    Proper description of uniform circular motion

    "Proper" description of uniform circular motion Homework Statement Hey guys, the world's a great place because I just finished my archeology term paper. ...so now I have to focus on this physics. I was just wondering if something's correct. Say I have a mass, like a puck, moving around on...
  16. P

    Uniform Circular motion, angular velocity and Friction

    Homework Statement A 7.00 g coin is placed 17.0 cm from the center of a turntable. The coin has static and kinetic coefficients of friction with the turntable surface of \mus = 0.850 and \muk = 0.540 What is the maximum angular velocity with which the turntable can spin without the coin...
  17. A

    Uniform Circular Motion: Bead on a String Problem Solution

    Homework Statement A 100 g bead is free to slide along an 80 cm 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. (a) Find the tension in the string. (b) Find...
  18. L

    Newtons Laws with Uniform Circular motion

    Homework Statement An airplane is flying in a circle at a speed of 480km/h. It wings are tilted at 40 degrees to the horizontal. What is the radius of the circle in which the plane is flying? Assume that the required for is entirely provided by "aerodynamic life" that is perpendicular to the...
  19. N

    Solving Uniform Circular Motion: 0.150-kg Ball on a 1.10-m Cord

    Homework Statement A 0.150-kg ball on the end of a 1.10-m-long cord (negligible mass) is swung in a vertical circle. Homework Equations Total net force = mass*centripetal acceleration = mass*(velocity squared)/radius The Attempt at a Solution The question I have is that... I'm...
  20. H

    Quick sign question for uniform circular motion

    Homework Statement what is the maximum speed with which a 1500kg car can make a left turn around a curve of radius 50m on a level road without sliding? Homework Equations The Attempt at a Solution i already got the answer...but my question is: f_s points left and the...
  21. C

    Simple Harmonic Motion- From Uniform Circular Motion

    Homework Statement I don't have a homework question exactly, but I need help with an equation please. Angular frequency: W= 2 pi/T = 2(pi)(f) f= frequency And- W = square root of (k/m) k = spring constant m= mass So, wouldn't T = 2 pi / square root of (k/m) ?? My...
  22. P

    Understanding Velocity and Acceleration in Uniform Circular Motion

    Homework Statement how does velocity and acceleration change in circular moton Homework Equations The Attempt at a Solution I know when a object is circular motion the velocity is tangential to the motion also, acceleration centripital, sum of the forces which points to a center...
  23. S

    Uniform circular motion and acceleration

    Homework Statement It is common to see birds of prey rising upward on thermals. The paths they take may be spiral-like. You can model the spiral motion as uniform circular motion combined with a constant upward velocity. Assume a bird completes a circle of radius 8.00 {\rm m} every 5.00 {\rm...
  24. P

    Velocity of an object in uniform circular motion

    Homework Statement What is the relationship between centripetal force and velocity What is the relationshio between the radius of the object and the velocity Homework Equations Not really any [b]3. The Attempt at a Solution [/b I believe a graph of centripetal force and velocity is...
  25. G

    Uniform Circular Motion Question

    On a circular racetrack, a car travels 2.0km at a speed of 120 km/h in completing one lap. A) What is the change in velocity in one quarter of a revolution? B) What is the change in velocity in half a revolution? Thanks for the help.
  26. T

    Understanding Newton's Laws through an Experiment on Uniform Circular Motion

    Homework Statement I've done an experiment on uniform circular motion. Pretty much, there is a hollow tube and a strong goes through it. One one end is a stopper and on the other is a weight. I had to spin the stopper side, buy keeping hold of the hollow tube, keeping the string at a constant...
  27. C

    Uniform circular motion on a table

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  28. R

    Projectile, and uniform circular motion questions

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  29. H

    Uniform circular motion equation

    ok so we did a lab. By looking at the graph, we determined that force of tension is proportional to frequency of revolution radius is indirectly proportional to the frequency of revolution mass is indirectly proportional to the frequency of revolution the next part of the question is...
  30. S

    Uniform circular motion of a particle

    Homework Statement A particle is moving at a constant speed around a circle of radius 1.5 meters, and it completes 4 revolutions in 6 seconds. a) What is its speed? b) What is its radial acceleration? c) In which direction does ar point? d) What is it tangential acceleration, at...
  31. C

    Newton's 2nd Law for a Particle in Uniform Circular motion

    1. A 4.0kg object is attached to a vertical rod by 2 strings. Object roatates in a horizontal circle at a constand speed 6.00 m/s. Find the tention in the upper and lower string. The strings are 2 meters long. the distance between the attachment points for each string is 3 meters. 2...
  32. S

    How Do Tensions in Upper and Lower Strings Differ in Uniform Circular Motion?

    Homework Statement A 4.00 kg object is attached to a vertical rod by two strings. The object rotates in a horizontal circle at constant speed 6.00m/s. Find the tension in the upper string and the lower string. Homework Equations C=2\pir T=(M)V^2)/r [b]3. The Attempt at a Solution [...
  33. A

    Uniform circular motion and coordinate system

    2. In the figure below the particle P is in uniform circular motion. The motion is centered on the origin of an xy coordinate system. (a) At what values of \vartheta is the vertical component r_{y} of the position vector greatest in magnitude? (b) At what values of \vartheta is the...
  34. S

    Understanding Uniform Circular Motion: Explained and Tested | Stephen

    I had a test today, there was a question about uniform circular motion. Isn't the velocity constant since the speed is constant? I know angular velocity is constant, but the question's answers only state constant speed or velocity. Thank you. Stephen
  35. E

    Deriving a Uniform Circular Motion Equation

    Derive the following equation: (mV^2/r)cos(x) = mgsin(x) I don't know how you would exactly derive the equation but you can simplify it to: tan(x)mg = mV^2 /r You can also divide by the m and get tan(x)g = V^2/r ... Any help is appreciated.
  36. J

    Uniform Circular Motion, Rotational Motion, Torque, and Inertia

    I'm in my first semester of Physics and i am having trouble understanding UCM, RM, Torque, and Inertia. The few things i do understand is Torque=rF(perpendicular)sin(theta) and that all points on a rigid rotating body have the same angular acceleration. please can someone help me?
  37. J

    Uniform Circular Motion in Lagrangian Formalism

    Problem: Consider a particle of mass m, constrained to move in a circle of radius r. Find the Lagrangian: Relevant Equations: L = T - V Where L is the Lagrangian, T is the kinetic energy, and V is the potential energy. My questions is this. T is the kinetic energy and would simply...
  38. Y

    Uniform circular motion radius

    In uniform circular motion, how is frequency proportional to: radius mass tension force? We did a lab where we connected rubber stoppers on one side of the string and masses to the other and spun it overhead and measured time taken for 10 cycles. I came up with: frequency is proportional...
  39. F

    Uniform Circular Motion of a stone

    Homework Statement A stone at the end of a sling is whirled in a vertical circle of radius 1.00 m at a constant speed vi = 2.40 m/s as in Figure P4.57. The center of the string is 1.50 m above the ground. http://xs124.xs.to/xs124/08095/p4-57alt_1_285.gif I solved these: (a) What is the...
  40. J

    Force for uniform circular motion

    [SOLVED] Force for uniform circular motion Homework Statement A 61.7 kg ice skater is moving at 3.55 m/s when she grabs the loose end of a rope, the opposite end of which is tied to a pole. She then moves in a circle of radius 0.545 m around the pole. The acceleration of gravity is 9.8 m/s^2...
  41. clope023

    Giant Swing, Uniform Circular Motion

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  42. I

    Uniform circular motion of satellite

    [b]1. An Earth satellite moves in a circular orbit 735 km above the Earth's surface. The period of the motion is 99.3 min. (a) What is the speed of the satellite?(b) What is the magnitude of the centripetal acceleration of the satellite? [b]2. a = v^2/r T=2(pi)r/v [b]3. i needed...
  43. B

    Calculating Mass from a Ferris Wheel Scale Reading

    Homework Statement A woman rides on a Ferris wheel of radius 16 m that maintains the same speed throughout its motion. To better understand physics, she takes along a digital bathroom scale (with memory) and sits on it. When she gets off the ride, she uploads the scale readings to a computer...
  44. S

    Uniform circular motion problems

    [SOLVED] Uniform circular motion problems Homework Statement A pilot of mass 50kg comes out of a vertical dive in a circular arc such that his upward acceleration is 8.5g Homework Equations a) What is the magnitude of the force exerted by the airplane seat on the pilot at the bottom of...
  45. S

    How Do You Calculate Net Force of Tension in Uniform Circular Motion?

    Homework Statement A 100 g bead is free to slide along an 80 cm 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 I know this question has been posted before...
  46. B

    Uniform Circular Motion of an object

    Homework Statement A horizontal force of 210N is exerted on a 2.0kg object as it rotates uniformly on a horizontal plane with a radius of 0.9m. Calculate the speed of the object. Homework Equations I THINK the relevant equations for this problem are v=2\Pir/T and ar=v^2/r. The...
  47. D

    Uniform Circular Motion of a satellite

    Problem: I have these exercises that I need help with. They look easy and I have an idea on what to do, but the answer I get is not right. I know I'm doing something wrong and I need any help I can get. Homework Statement 1.) An Earth satellite moves in a circular orbit 640 Km above...
  48. K

    Uniform circular motion and coefficient of friction

    Homework Statement You are standing on a merry-go round spinning at 12 rpm. The radius of the merry-go round is 5 meters, and you have a mass of 57kg. What static frictional force between your shoes and the merry-go round is required to keep you from flying off? Homework Equations...
  49. S

    Uniform circular motion car problem

    Homework Statement a cart with a person in passes over a circular arch at a constant speed v who's radius is r. Does the maximum speed the cart can go without leaving the tracks depend on the mass of the person, the mass of the cart, both, or neither? Homework Equations Fg=mg...
  50. S

    Maximum Speed and Banked Turns in Circular Motion

    Homework Statement Part A) A car drives over a circular hill (hill radius is r). Is there a maximum speed that the car can have and still remain in contact with the road? If not, why not. If so, find an expression for the maximum speed. Part B) Now, the car (with mass = 1000kg) enters a...
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