What is Centripetal: Definition and 1000 Discussions

A centripetal force (from Latin centrum, "center" and petere, "to seek") is a force that makes a body follow a curved path. Its direction is always orthogonal to the motion of the body and towards the fixed point of the instantaneous center of curvature of the path. Isaac Newton described it as "a force by which bodies are drawn or impelled, or in any way tend, towards a point as to a centre". In Newtonian mechanics, gravity provides the centripetal force causing astronomical orbits.
One common example involving centripetal force is the case in which a body moves with uniform speed along a circular path. The centripetal force is directed at right angles to the motion and also along the radius towards the centre of the circular path. The mathematical description was derived in 1659 by the Dutch physicist Christiaan Huygens.

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  1. F

    Centripetal acceleration and airplane lift

    Homework Statement An airplane is flying in a horizontal circle at a speed of 460 km/h (Fig. 6-42). If its wings are tilted at angle θ = 37° 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...
  2. J

    Centripetal Force Skater Speed Question

    Homework Statement A skater holds her arms outstretched as she spins at 225 rpm. What is the speed of her hands if they are 152 cm apart? The Attempt at a Solution I converted 225 rpm to 3.57 rps and found the angular velocity (23.56 rad/s) to plug into the equation v=wr, but it didn't...
  3. C

    How Do You Calculate the Speed and Tension in a Rotating Amusement Park Ride?

    Homework Statement A) An amusement park ride consists of a rotating circular platform 10.8 m in diameter from which 10 kg seats are suspended at the end of 2.34 m massless chains. When the system rotates, the chains make an angle of 29.4◦ with the vertical...
  4. D

    Centripetal Acceleration and Finding an Angle

    Homework Statement An old streetcar rounds a flat corner of radius 9.1 m, at 16 km/h. What angle with the vertical will be made by the loosely hanging hand straps? Homework Equations The equations I know: acceleration = velocity squared / radius (a = v^2 / R) Force = mass *...
  5. T

    Centripetal force of rotating mass vs. flowing mass

    Hi, thanks in advance for any help and info. Have two conditions. The first condition is a mass of water spinning as a fixed mass. Say we have a rectangular mass .25 inches tall, 2 inches long and .50 thick spinning at 3000 RPM with its center of mass at R = 2.00 inches. (Please see first...
  6. P

    Centripetal Acceleration check my reasoning

    Homework Statement ok well then... we did a lab were you have a hanging mass attached to a stirng that went through a straw and was attached to a rubber stopper. The lab was to find the mass of the rubber stopper once you know the velocity. So I was woundering if this looks correct...
  7. P

    Confused About Calculating Period in Circular Motion?

    EDIT: I figured out what I did wrong. T=\frac{2{\pi}r}{v}, not \frac{2{\pi}r}{\omega}. Now it all falls together.Homework Statement A small disk of mass m_1 on a frictionless table is attached to one end of a string. The string passes through a hole in the table and an attached narrow, vertical...
  8. D

    Finding Centripetal Force in a Closed-Loop String

    Homework Statement I never thought I would have this kind of elementary problem consider a string closed-loop spinning around an axis, and its shape is a circle, I wanted to find the centripital force at each point. (uniform density is assumed). I have problem expressing the mass...
  9. B

    Centripetal Force / Tension / Speed

    Centripetal Force / Tension / Speed (HELP!) 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...
  10. J

    Find the ration of the centripetal accelaration

    The large blade of a helicopter is rotating in a horizontal circle. The length of the blade is 6.7m, measured from its tip to the center of the circle. find the ration of the centripetal accelaration at the end of the blade to that which exists at a point located 3.0m from the center of the...
  11. T

    Centripetal force on an industrial fan

    I make industrial fans of which use impellers that can reach up to 80 m/s tip speed, i also learned that it shouldn't be tip speed but tip acceleration because the impeller is constantly changing direction it should be 80 m/s^2. So to calculate the force should i use force = Ma or m x...
  12. D

    Centripetal force and acceleration

    Homework Statement The moon takes 27.3 days to circle Earth and its centre is located 3.84 x 108 m from the centre of Earth. What is the Moon’s acceleration? Homework Equations a=v^2/r, a=4(pi)^2mr/T^2 The Attempt at a Solution i don't know how to answer this question becuase i...
  13. D

    Centripetal Force: Calculating Radius of Curve for 1.00 x 10^3 kg Car

    Homework Statement A 1.00 x10^3 kg car is moving through a flat curve on a road at a velocity of 30.0 m/s. If the coefficient of friction between the road and the tires is 0.600, the radius of the curve is Homework Equations r=v^2/(coefficitent of friction)(g), r=mv^2/F The Attempt...
  14. Y

    How Do You Calculate Radial Acceleration and Velocity in Circular Motion?

    Homework Statement A ball swings in a vertical circle at the end of a rope 1.50 m long. When the ball is 36.9° past the lowest point on its way up, its total acceleration is (-22.5i, 20.2j) m/s2. At that instant, (a) determine the magnitude of its radial acceleration, and (b) determine the...
  15. O

    Can Centripetal Force create Gravity?

    What I'm trying to get at is this, can a spinning framework of rings build enough centripetal force to keep a mass of liquid at the centre of the frame work? And if so what would be the relationship and conditions that would have to be met? Really need help:|
  16. 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...
  17. S

    How Does Halving the Radius Affect the Period in Centripetal Acceleration?

    What happens to the period when you cut the radius in half for a centripetal acceleration problem? a=V^2/r T=2pi*r/v I need some background on this question. I believe the answer is the period is decreased by a factor of 2. I am just slightly confused.
  18. F

    Understanding Centripetal Force in a Pendulum System

    "A 0.400-kg pendulum bob passes through the lowest part of its path at a speed of 3.00 m/s. What is the tension in the pendulum cable at this point of the pendulum is .8 meters long?" I would like to ask for some help on understanding centripetal force in this particular situation. I realize...
  19. S

    Centripetal Acceleration circular disk

    Homework Statement A circular disk of radius 30 cm is rotating with an angular acceleration of 1 radian/ s2. What is the tangential acceleration of a point on the rim of the disk? What is its centripetal acceleration if the angular speed is 3 rev / s? Homework Equations tangential...
  20. O

    G-Forces on a Rollercoaster Ride: Exploring Centripetal Acceleration

    Homework Statement A rollercoaster car is going over a hill, with a person sitting with -no- restraints. The velocity of the car and radius of the hill are such that the centripetal acceleration of the cart is 15 m/s^2. What is the relative g environment (for the rider) and how many g's does...
  21. Q

    Centripetal thrust need at high-speed

    Hi Relativists My puzzle is inspired by Stephen Baxter's novel "Ring" in which the starship "Great Northern" flies out and back to Earth in a proper time of 1,000 years, but on Earth 5,000,000 years have passed. The description in the novel suggests that the starship flies in a loop, so I...
  22. S

    Centripetal Force: Why Does Friction Provide It?

    My textbook says that the requisite centripetal force for the circular motion of a vehicle is provided by friction. I don't get that .... i mean , shouldn't friction oppose relative motion ...so , seeing as the direction of motion of the car is along the tangent to the curve , shouldn't friction...
  23. T

    Calculating Centripetal Acceleration and Gravitational Force in a Hydrogen Atom

    Homework Statement The mass of an electron is 9 x 10-31 kg. The mass of a proton is 1.7 x 10-27 kg. The proton and electron are about 1.0 x 10-10 m apart in a hydrogen atom. What force of gravitation exists between the proton and the electron of a hydrogen atom? What is the centripetal...
  24. P

    Deriving Centripetal Acceleration

    Hi. I'm trying to derive a = (v^2)/r from the position of a particle moving in a circle. Since the equation for a particle moving in a circle is x(t) = r(isin(wt) + jcos(wt)) where w is constant. I took two derivatives to find it's acceleration. I got a(t) = -rw^2(icos(wt)+jsin(wt)). Now I'm...
  25. E

    Centripetal Force: Ball in Vertical Circle at Constant Speed

    A ball is swung around in a vertical circle at constant speed. Where is the ball when the tension in the rope is at maximum / minimum? I know where the ball is, how would I explain it?
  26. D

    Ball tied to string- centripetal force

    Homework Statement A ball, mass m = 1.5 kg is twirled at constant speed v at the end of a massless string in a vertical circle of radius r = 1.2 m. The period for this uniform circular motion is T = 1.3 s. Free body diagrams for the ball at the top and at the bottom of the circle are shown...
  27. M

    Why centripetal accel is from an internal force?

    Can i ask sth? Why centripetal accel is from an internal force? Usually what type of forces can be considered as external force, besides friction? And, for static equilibrium, do we only use the eqn: sum of forces equals zero, or we can also apply sum of moments equals zero? Thanks!
  28. M

    What Is the Maximum Speed to Navigate a Banked Curve Without Sliding?

    Homework Statement A concrete highway curve of radius 70.0 m is banked at a 13.0 degree angle. What is the maximum speed with which a 1900 kg rubber-tired car can take this curve without sliding? (Take the static coefficient of friction of rubber on concrete to be 1.0.) Homework Equations...
  29. S

    Questions about centripetal force

    1. Mr. B takes his grade 12 physics class to the local amusement park at Hopedale Mall to conduct some experiments on friction and centripetal force in the gravitron. The Gravitron is an amusement park ride shaped like a vertical cylinder with a radius of 7m. Riders stand with tier backs against...
  30. I

    Grade 12 Physics, centripetal force and projectile motion

    Hello Physics Forum, I am new member and this is my first Thread. :smile: While onto the problem. I have been stuck on this particular for well over a week. I do not get the excat answer and to me my solution seems logically. Homework Statement An Australian bushman hunts kangaroos with a...
  31. E

    Centripetal Acceleration of space shuttle

    Homework Statement "The Space shuttle is located in a low orbit at a distance of 1.6 x 10^5 m above the surface of the earth. If gravity is the only force acting on the shuttle, what is the shuttle's speed while in this orbit?" Variables: Shuttle Velocity = ? r = 1.6e5 + 6.38e6...
  32. E

    Centripetal Acceleration lab question

    [b]1. This is more of a general question about a lab report I'm doing: The purpose of this lab is to find if the acceleration of a person sitting on the end of a steel beam is moving at a constant acceleration, if they aren’t accelerating, or if acceleration changes with time. I have all my...
  33. H

    Clearance with centripetal force relationship to freq, radius, and mass.

    I was doing a lab in which i had a string passing through a glass tube, on one end we had washers while on the other end we had a rubber stopper. Now i understand that the washer will have force of gravity on them which will create tension which will be the centripetal force. So when i begin...
  34. I

    Centripetal and Tangential Acceleration of drill bit

    Homework Statement An electric drill bit starts from rest and rotates with a constant angular acceleration. After the drill has rotated through a certain angle, the magnitude of the centripetal acceleration is twice the magnitude of the tangential acceleration. What is the angle? Homework...
  35. R

    Formula for the velocity of the centripetal force

    Hi, can anyone please tell me the fomular for the velocity of a centripital force with the radius of 100 cm, with one revolution revolting in 0.98 seconds?
  36. S

    Centripetal Force HW: Inclined Plane, Angle 30°, Mass 2kg, Radius 3m

    Homework Statement an inclined plane with angle 30 degrees has a mass on it. The static friction coefficient is 0.2 and the mass is 2 kg. The system then rotated to form a circular path with radius 3 m. Find the angular frequency so the mass will stay stationary. Homework Equations...
  37. T

    Centripetal Acceleration of Stone Problem

    Homework Statement A stone at the end of a sling is whirled in a vertical circle of radius 1.20 m at a constant speed v0 = 1.50 m/s. The center of the sling is 1.50 m above the ground. What is the range of the stone if it is released when the sling is inclined at 30 degrees with the...
  38. H

    Need Help Understanding Concepts of Centripetal Force.

    Now as I understand, a force must be present to cause centripetal acceleration. So as a car goes around a circular arc it is friction between the tires which causes centripetal acceleration. So since the car is turning around the curve the friction will be perpendicular to the instantaneous...
  39. Z

    Centripetal motion and universal gravitation question: Mars and Sun question

    Homework Statement Mars travels around the Sun in 1.88 (Earth) years, in an approximately circular orbit with a radius of 2.28 x 10^8 km Determine a) the orbital speed of Mars (relative to the Sun) b) the mass of the Sun Homework Equations acceleration centripetal = 4(pi^2)(r) /...
  40. Z

    Centrifugal and centripetal force question: race-car and banked curve question

    Homework Statement A race-car driver is driving her car at a record-breaking speed of 225kh/h. The first turn on the course is banked at 15 degrees, and the car's mass is 1450kg. a) Calculate the radius of the curvature for this turn b) Calculate the centripetal acceleration of the car...
  41. P

    Centripetal Force: Calculating Bank Angle for Plane Circling Airport

    Homework Statement As your plane circles an airport, it moves in a horizontal circle of radius 2100m with a speed of 400km/h. If the lift of the airplane's wings is perpendicular to the wings, at what angle should the plane be banked so that it doesn't tend to slip sideways Homework...
  42. M

    What is the Centripetal Acceleration of Earth's Orbit Around the Sun?

    Homework Statement Observing an orbit of Earth around the sun, calculate the centripetal acceleration of Earth. Homework Equations Fc = mv^2/R Only the distance aka radius was provided, to be 1.496x10^11m. The Attempt at a Solution No mass of Earth provided.
  43. G

    Clarifying the Relationship Between Centripetal Force and Gravity

    Hi, I'm currently taking 1st semester Physics and am trying to understand centripetal force relative to the Earth's rotation. From what I understand (using a bucket of water tied to a string as an example), swinging a bucket in a circular motion, when the bucket is completely above your...
  44. E

    Centripetal Force: 80kg Pilot in Jet at 305m/s

    Homework Statement An 80 kg pilot, makes a loop the loop in a jet, the jet maintains a constant speed of 305 m/s and the radius of the loop is 1.900km. What is the apparent weiht that the pilot feels( Force) at the bottom of the loop the loop. Homework Equations Acp=w^2/r w=(v/r) F= ma...
  45. L

    Centripetal Acceleration

    Homework Statement What would Earth's rotation period have to be for objects on the equator to have a centripetal acceleration equal to 9.8 m/s^2? ____ min Homework Equations Centripetal acceleration is equal to velocity * (2PI/T), where T is the period in seconds. The...
  46. U

    Centripetal Acceleration of hard drive

    Homework Statement A computer is reading data from a rotating CD-ROM. At a point that is 0.030 m from the center of the disc, the centripetal acceleration is 120 m/s2. What is the centripetal acceleration at a point that is 0.050 m from the center of the disc? Homework Equations ac =...
  47. A

    What is the speed of the roller coaster at the bottom of the dip?

    A roller coaster at an amusement park has a dip that bottoms out in a vertical circle of radius r. A passenger feels the seat of the car pushing upward on her with a force equal to three times her weight as she goes through the dip. If r = 22.0 m, how fast is the roller coaster traveling at the...
  48. S

    Centripetal acceleration and static friction

    Homework Statement A coin is placed on a record that is rotating at 33.3 rpm. If the coefficient of static friction between the coin and the record is 0.2, how far from the center of the record can the coin be placed without having it slip off? Homework Equations mv^2/r = mg(mu)...
  49. B

    Please help circular motion/ centripetal acceleration and more

    Homework Statement Ok, I am a straight A student in math so you think Physics would be easy right? Not exactly. I really need someone to explain this stuff to me. Its probably really easy if it was explained to me correctly but my teacher is not the best when it comes to breaking things...
  50. L

    Centripetal Force acceleration

    1. A computer is reading data from a rotating CD-ROM. At a point that is 0.0330 m from the center of the disk, the centripetal acceleration is 264 m/s2. What is the centripetal acceleration at a point that is 0.0702 m from the center of the disc? 2. ac=v2/r 3. So my thoughts here...
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