What is Circular motion: Definition and 1000 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.

View More On Wikipedia.org
Recent contents Top users
  1. M

    Banked roads -- circular motion and gravitation

    Homework Statement If a curve with a radius of 88m is perfectly banked for a car traveling at 75km/h, what must be the coefficient of static friction for a car not to skid when traveling at 95 km/hr 75km/h = 20.8m/s 95km/h = 26.4m/s Homework Equations Fr=mv^2/r Fr=centripetal force m = mass r...
  2. O

    Can someone explain this quote about centripetal motion?

    Homework Statement In describing a wheel's circular motion: "Circular motion arises purely from the resistance of the ground upon which it is applied…this resistance is equal to the force which draws the wheel in the right line" Homework Equations F=m(v^2/r) The Attempt at a Solution Is this...
  3. R

    Using Kepler's 3rd Law to find Period of Venus

    Homework Statement Deduce, from the equations employed in Q4 and Q5, the exponent n in the equation: T = k rn where k is a constant and T is the period of a satellite which orbits at a radius r from a massive object in space. Hence, how long is the “year” on Venus if its distance from the Sun...
  4. F

    Centripetal force and spinning discs

    Apologies for a possibly very basic question. I was recently asked by someone to explain to them the answer to the following classical mechanics (uniform circular motion) problem: Consider two discs of different radii, attached to one another such that they are concentric, and each containing a...
  5. Vavi Ask

    Radial force in a circular motion

    Homework Statement Given- Mass of particle=m Radius of the circular path=r Magnitude of linear momentum= p Find the radial force acting on the particle. Homework Equations p=mv acentripetal=v2/r The Attempt at a Solution Fradial=macentripetal =mv2/r =mv2×m/r×m...
  6. Hardikph

    Is Δθ in a circle equal to the angle in a velocity vectors triangle?

    How is Δθ in circle equals to angle in velocity vectors triangle? I tried using simple geometry but I can't.
  7. F

    Understanding Circular Motion: The Relationship Between Force and Velocity

    If a force acts on an object perpendicular to its velocity, why does the speed remains unchanged? Wouldn't the force give rise to a vertical component of velocity on the object and thus increase the speed of the object?
  8. S

    Questions about understanding circular motion & the forces involved

    Hey, I'm having some difficulty in understanding circular motion and it's forces. Here is the situation I'm on: Imagine you are on a smooth turn-table with smooth shoes and the table starts spinning. Because of inertia, and because the frictional force is not nearly enough to keep you going in a...
  9. W

    Required conditions for vertical circular motion to occur?

    For the case of a particle attached to an inextensible string which is hanging at rest and then provided an impulse horizontally, what conditions must the system meet in order to allow for COMPLETE circular motion. I am well aware the tension at the apex of the motion must be satisfy one of the...
  10. N

    How Do You Calculate Acceleration in a Limacon-Shaped Path?

    Homework Statement The rod OA rotates clockwise with a constant angular velocity of 6 rad/s. Two pin-connected slider blocks located at B move freely on OA and the curved rod whose shape is a limacon described by the equation r = 200*(2-cosθ) mm. Determine the magnitude of the acceleration of...
  11. N

    Circular motion -- Car on a circular track

    Homework Statement A car has an initial speed v0= 20m/s. It increases its speed along the circular track at s=0, at=(0.9s) m/(s2), where s is in meters. Determine the time needed for the car to travel 35m. The radius of curvature of the track is 40m. Homework Equations an = v^2/p a = dv/dtThe...
  12. E

    Can a Stone Remain in Circular Motion if Tension Equals Zero Before Velocity?

    Let's say I have a stone tied to a string and I'm spinning it vertically. Now, if I provide an initial velocity such that the velocity of the stone = 0 at an angle greater than 0 from the horizontal(visualize it in the "first quadrant") the eq of motion would be: T+mgsin (theta) = mv^2/r. If the...
  13. diazdaiz

    Kinematics and dynamic circular motion of conical pendulum

    Homework Statement [/B] find the period with only using L (for the long of the rope), R (for the radius), M (for the mass), and G (for the gravity) Homework Equations V=ωR Fcentripetal = ##\frac {MV^2} {R}## Fgravity = MG phytagoras basic trigonometry The Attempt at a Solution [/B] i have...
  14. physea

    Normal reaction in banked road circular motion

    Homework Statement Homework Equations ΣF=0 The Attempt at a Solution Basically I don't agree with this solution, I think it is R1 + R2 - mgcos5 + mv^2sin5/r = 0. Can you help me please? thanks!
  15. physea

    Normal reaction in banked road circular motion problem

    What is the equation of forces please for the axis parallel to the banked road? Is it R1+R2-mgcosθ=mV^2/r or R1+R2-mgcosθ=-mV^2/r? Can you advise me please?
  16. RoboNerd

    Question on finding maximum magnitude of acceleration

    Homework Statement An object is moving in the xy-plane according to the equations x(t) = 3sin(3t) and y(t) = 4cos(3t). What is the maximum magnitude of the particle's acceleration? 1) 5 m/s22) 15 m/s23) 30 m/s24) 36 m/s2 [the accepted answer]5) 45 m/s2 Homework Equations x(t) =...
  17. RoboNerd

    Implementing angular momentum approach in problem

    Homework Statement An object is in uniform circular horizontal motion at the end of a chord of length L. Its tangential speed is v. The chord is pulled into length 0.5L in such a way that the tension in the chord remains constant. As a result, the tangential speed: a) remains constant b)...
  18. RoboNerd

    Question kinetic energy in circular motion

    Homework Statement An object moves in uniform circular motion. Its kinetic energy is directly proportional to: I. centripetal force II. radius of the circle III. the period of circular motion Homework Equations I took the universal gravitational law G* m1 * m2 /r^2 = m2 * v^2/r and then I...
  19. UMath1

    Why is the speed of orbiting satellites constant?

    As I understand it, satellites orbiting the Darth are constantly falling but keep missing. Why then is their speed constant? Why do they not tangentially accelerate like spaceships do when using a gravity assist? I understand that the force of gravity is perpendicular to the satellites motion...
  20. RoboNerd

    Question about circular motion of planets

    Homework Statement Homework Equations I know that Fc = m * centripetal acceleration, where the Fc = the force of gravity The Attempt at a Solution [/B] I was able to use process of elimination to get B for 25 correctly, but I am not able to understand how it is the right answer. How can...
  21. A

    Acceleration around a running track

    Homework Statement He is running around a running track training for a 400m race. His velocity is 5.11m/s around the circular end of the track, which has a radius of 31.8m. I'm trying to find his acceleration which I know is 0.821ms-2 but I can't find out how to get it. Homework Equations v=rω...
  22. BiGyElLoWhAt

    I Doppler shift for an observer in circular motion

    Say we have an observer in perfectly circular motion around a source, like a star. Is it reasonable to apply the angle change formula ##cos \theta_o = \frac{cos \theta_s - \frac{v}{c}}{1-\frac{v}{c}cos \theta_s}## and then take the component of the motion parallel to the light wave in the...
  23. sushichan

    [Mechanics] Circular motion outside sphere

    Homework Statement A marble rolls from the top of a big sphere. What is the angle θ when the marble is about to leave the sphere? Assume a zero speed at the top. Homework Equations The question came from the chapter Mechanics - circular motion. The Attempt at a Solution I can't conceive what...
  24. L

    Falling rotating sphere and displacements

    Homework Statement Homework Equations How to locate the point P and C after 0.5s from their initial position ? The Attempt at a Solution Well i don't know whether it would be correct way to start the problem i.e find the centripetal acceleration .
  25. Oribe Yasuna

    Circular Motion in a Simple Mass Spectrometer

    Homework Statement In the simple mass spectrometer shown in the figure below, positive ions are generated in the ion source. They are released, traveling at very low speed, into the region between two accelerating plates between which there is a potential difference ΔV. In the shaded region...
  26. Abhijeet Verma

    Time Period of Vertical Circular motion

    Since the latex is not appearing, I request you to please click https://brilliant.org/discussions/thread/time-period-of-vertical-circular-motion/ , to view with complete formatting. Please help. Thanks. P.S-This is not schoolwork or homework...
  27. popo

    How Does Rolling Friction Affect a Toy Train's Motion on a Circular Track?

    Hi, thanks for taking a look! A toy train rolls around a horizontal 1.4-m-diameter track. The coefficient of rolling friction is 0.12. (a) What is the magnitude of the train's angular acceleration after it is released? (b) How long does it take the train to stop if it's released with an...
  28. S

    Horizontal circular motion problem, what am doing wrong?

    Homework Statement The County Fair Swing carries the mass of riders and chairs in a circular path in a horizontal plane while suspended by cables or chains. Let's assume that: Each chair with riders is supported by a single cable The tension in the cable equals 2 x the total weight riders...
  29. D

    Simulated circular motion on a roller coaster

    Homework Statement A roller coaster at the Six Flags Great America amusement park in Gurnee, Illinois, incorporates some clever design technology and some basic physics. Each vertical loop, instead of being circular, is shaped like a teardrop. The cars ride on the inside of the loop at the top...
  30. T

    Find the time for the string to break

    Hi all! I am currently working on an assignment for my dynamics course in which we need to create our own "real world" problems. I chose to do a problem which would solve the time at which the string of a lanyard would break when it is swung in a circle. My problem is with my end numbers. They...
  31. Neeps

    Sailboat rudder physics, and water flow estimate

    Hi. I'm a computer science student developing a kalman filter for autonomous sailboat, but I severely lack knowledge of the physics behind sailboats. I have a wind sensor giving data about wind speed and wind velocity, problem is the data is unreliable. So i thought that i could estimate what...
  32. R

    Uniform circular motion - finding velocity

    Homework Statement Homework Equations radial acceleration = v^2/R The Attempt at a Solution I'm unsure if we have to mention the tension of the cable, but I'm guessing L2 will suffice? Correct me if I am wrong. Anyways, I drew the diagram from a side view (kind of like a circular pendulum)...
  33. Nikki1357

    How fast to spin object hanging by thread to break thread

    Homework Statement If an object is hanging by a thread, how fast must it be twirled around in order to break the thread? (must also provide explanation of why this is the velocity). As a part of a lab, pick a certain mass. Attach to light string (easily breaks) and pull the string through a...
  34. K

    Circular Motion and Energy Calculations

    Homework Statement A) An object moving along the x-axis is acted upon by a force Fx that varies with position as shown. How much work is done by this force as the object moves from x = 2 m to x = 8 m? B) A 50-kg child riding a Ferris wheel (radius of wheel R = 10 m) travels in a vertical...
  35. M

    Finding number of rotations till arm breaks (circular motion)

    Homework Statement A 400 g steel block rotates on a steel table while attached to a 1.20 m -long hollow tube. Compressed air fed through the tube and ejected from a nozzle on the back of the block exerts a thrust force of 4.91 Nperpendicular to the tube. The maximum tension the tube can...
  36. P

    Circular motion and acceleration

    If you are twirling a rock around your head with a rope (assuming it is uniform circular motion), then the only acceleration that is acting is radial. So if you take a look at the rock at any given instant, its velocity is perpendicular to its acceleration. My question is, why does the rock not...
  37. Dietrichw

    Projectile and Uniform Circular Motion

    Homework Statement An object is launched horizontally from the highest peak on the Moon's surface. Calculate (a) the launch speed required so that the object travels completely around the Moon and returns to its original position, and (b) the time required to return to the launch point. Assume...
  38. Priyadarshini

    Circular Motion and resultant force

    Homework Statement Homework Equations F= mv^2/r v = angular vel* r The Attempt at a Solution resultant force= ma-frictional force = mv^2/r - mg*meu = (angular vel)^2mx - mg*meu But then how do I get the angular speed when I don;2 know the resultant...
  39. NihalRi

    Circular motion , the loop the loop

    Homework Statement The loop-the-loop machine has radius R of 18m (a) What is the minimum speed at which a cart must travel so that it will safety loop the loop (b) what will the speed at the top be in this case Homework Equations Centipetal force = m*v^2/r Kinetic and potential energies =...
  40. S

    Equation for Simple Harmonic Motion?

    In Simple Harmonic Motion, can (k/m) = ω2 be expressed for all SHMs or only the ones in which the mass due to which the SHM is being executed is performing a circular motion? Since for example, in the case of spring, there is no circular motion involved, so omega should not be defined for...
  41. RoboNerd

    Conceptual Question on acceleration and circular motion

    Homework Statement If a roller coaster car enters the circular-loop portion of the ride and navigates it successfully, then the net force on the car at its topmost point is straight down. Then why does not the car fall down? So I am having issues understanding my textbook's solution to the...
  42. M

    Roller coaster - uniform circular motion

    Hi, I have been studying up on circular motion in the vertical plane and I am happy with all the math/theory that I have read explaining the normal force and weight force and the feeling of being "heavier" and "lighter". My question is about the top of the hill/ride, The forces acting on you at...
  43. K

    How Does Pulling the String Affect the Speed of a Ball in Circular Motion?

    Homework Statement Ball of mass=m on the frictionless table is connected to a string that passes in hole that is in table. The ball is set into a circular motion on a circle of radius = R. If the string pulled from the bottom, withe the force F, so that the radius of motion of ball would...
  44. D

    Calculating Revolutions for a Spinning Wheel | Circular Motion Problem

    Homework Statement A wheel spins at an angular speed of 2.50 rad/s for a total of 30.0s. How many complete revolutions will the wheel make during this time? A) 31.4 rev B) 19.3 rev C) 11.9 rev D) 75.0 rev Homework Equations W=Wo+(alpha)(t) θ=θo+Wot+1/2(alpha)t^2 W^2=Wo^2+2(alpha)(θ-θo) The...
  45. C

    How to Calculate Average Velocity on a Circular Track?

    Homework Statement A car travels on a circular track at 20m/s. The track has a circumference of 2.0km. What is the average velocity of the car over one lap? Homework EquationsThe Attempt at a Solution Since the car is traveling at a constant speed of 20m/s, wouldn't the average velocity be...
  46. james_dear

    Orbit of Cube Planet: Physics Explained

    What is the physics behind a orbit a cube planet. Does the convential physics including keplars laws and circular motion still apply. Also The cube having a centre of mass posited in the middle of the cude does this mean it can be consider point mass and the same as spherical planet orbit? any...
  47. A

    Understanding Friction: Exploring Friction in Circular vs Straight Road Motion

    please explain the phenomenon of friction acting on a car moving in a circular track.also explain how is this friction static and how is this friction different from the friction acting on a car moving on a straight road.
  48. A

    Direction of friction when a body moves in a circular track?

    please explain why? Take 2 cases,and explain how is the direction of friction different in these 2 cases. CASE 1:uniform circular motion CASE 2:non uniform circular motion my thought was,friction opposes relative motion,so it must be tangential to the particle at each and every point. i very...
  49. Mr Davis 97

    Difference between circular motion and rotational motion

    I don't really understand the difference between uniform circular motion and rotational motion. I know that uniform circular motion deals with a body that is orbiting around a central point, with a centripetal force that is causing it to move in a circle. I know that rotational motion uses...
  50. Carson Birth

    Motion of a point mass (circular motion)

    Homework Statement A point mass, sliding over an even, horizontal plane is bounded on an inextensible, massless thread. During the motion, the thread is pulled by a force F with constant velocity ##v_{o} ## through a hole O. In the beginning (##t_{o} ## = 0) r(##t_{o} ##)=b holds (the length...
Back
Top