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. S

    Centripetal Force = Net Force?

    I'm doing a lab, and I need to determine the centripetal force of a ball tethered to a string, rotating around at a constant acceleration horizontally. In this instance, is the only force in the problem the centripetal force, in which case would also be the net force, or is there also a normal...
  2. M

    Total centripetal acceleration ringworld

    Homework Statement A) In Larry Niven’s science fiction novel Ringworld, a ring of material or radius 1.54 × 1011 m rotates about a star with a rotational speed of 1.4 × 106 m/s. The inhabitants of this ring world experience a normal contact force ~n. Acting alone, this normal force would...
  3. M

    Gravitational acceleration/ centripetal

    Homework Statement Given: G = 6.67259 × 10−11 N · m2/kg2 A satellite moves in a circular orbit around Earth at a speed of 3160 m/s. Find the satellite’s altitude above the surface of Earth. Answer in units of m. I'm not sure how to do this without the mass of Earth..don't you need it to plug...
  4. S

    Water in the Bucket: Free Body Diagram? (Vertical Centripetal Force)

    Water in the Bucket: Free Body Diagram?? (Vertical Centripetal Force) Homework Statement If a bucket tied to a rope is revolving vertically in an counter clockwise direction, what would be the Free Body Diagram of "water" in the bucket at the top position? Homework Equations There...
  5. M

    Please help on this centripetal force lab

    ok so I am sure you all know about the lab where u have to find relation between Fc frequency,radius,mass,velocity with stoppers and such. so my final discussion question states: It should be noted that in this investigation the radius of rotation is only an approximation,particulary at lower...
  6. E

    Troubleshooting Centripetal Force Lab Calculations: What Went Wrong?

    Homework Statement Since I ran out of time in class, I have to make up my own times for this lab using calculations. The lab consists of our providing a little force by shaking this tube. Inside this tube is a string, and at one end of the string is attached a hanging mass, the other end a...
  7. P

    Centripetal force and velocity help

    centripetal force (urgent) Homework Statement what should a centripetal force vs. velocity(speed) graph look like. what should a velocity(speed) vs. radius(of the circle) look like. what should a velocity(speed) vs. stopper mass graph look like. Homework Equations To find...
  8. K

    Centripetal Force and Banked Curves

    I've attempted to solve this problem but I'm not really sure if I'm doing it right. I've looked up other threads containing the same question, but they just don't have the answers I'm looking for. Thank you in advance to anyone who helps. Homework Statement A race-car driver is driving her...
  9. O

    Finding mass of a central body: centripetal forces and orbiting bodies

    Homework Statement One stellar mass is defined as the mass of our sun (1Ms = 1.99 x 1030 kg). ONe astronomical unit is defined as the length of Earth's semi-major axis (1AU = 1.49 x 1011 m). The star Epsilon Eridani in the constellation Eridanus has a planet (discovered in 2000) orbiting it...
  10. K

    Understanding Centripetal Net Force in Circular Motion

    Homework Statement If you swing a ball in a horizontal circle around your head, what is the direction and magnitude of the net force acting on the ball? Homework Equations The Attempt at a Solution I said none because the ball is moving at a constant velocity. Is this correct...
  11. N

    Centripetal Force, very simple.

    Homework Statement A man hanging upside down is holding a partner who weighs 475 N. Assume that the partner moves on a circle that has a radius of 6.50 m. At a swinging speed of 4.00 m/s, what force must the man apply to his partner in the straight-down position? Homework Equations...
  12. F

    Understanding Centripetal Force: Exploring the Curvature of Trajectories

    trivial centripetal force... hello forum, a simple, qualitative question. A centripetal force serves to curve the trajectory of an object (acceleration that only changes the velocity direction, not the magnitude). But why is the object not pulled inward as well? I can see the turning...
  13. E

    Centripetal acceleration of protons in an accelerator

    Homework Statement In a certain accelerator, protons of kinetic energy 1.6 x 10^-7 J move round a circular path of diameter 2000m . Calculate: (a) the centripetal acceleration (b) the mass ans for a is 9x10^13 ms-2, for b is 1.78 x 10^-24 kg Homework Equations centripetal...
  14. B

    Centripetal Force: Tire Radius Calculation for 5.0 10-3 kg Stone

    A stone has a mass of 5.0 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 rotating at 20 m/s, the stone flies out of the tread. The...
  15. W

    Centripetal Force Proportionality Check

    Homework Statement Write a proportionality statement for F, m, f and r using your three proportionality statements. Homework Equations F = centripetal force f = frequency m = mass r = radius F \propto f^2 r \propto F^2 m \propto F^2 The Attempt at a Solution m \propto...
  16. R

    Calculating centripetal acceleration

    A ball of mass m is suspended from a rope of length R. The ball is set into freely swinging circular motion in a vertical plane. The centripetal acceleration of the ball at the top of the circle is 13g. The centripetal acceleration of the ball at the bottom of the circle is closest to: A...
  17. F

    Calculating Centripetal force

    1. A bird of mass 0.211kg pulls out of a dive, the bottom of which can be considered to be a circular arc with a radius of 25.6m. At the bottom of the arc, the bird's speed is a constant 21.7m/s. Determine the magnitude of the upward lift on the bird's wings at the bottom of the arc. I am...
  18. B

    Tangential and Centripetal Acceleration

    Hi, I basically just have a concept question, if the tangential acceleration of an object is zero, can at the same time its centripetal acceleration be nonzero?
  19. G

    Amusement Park Centripetal Force Around A Loop

    In an amusement park ride called The Roundup, passengers stand inside a 18.0 m-diameter rotating ring. After the ring has acquired sufficient speed, it tilts into a vertical plane. Suppose the ring rotates once every 4.90 s. and the rider's mass is 58.0 kg. A.) With how much force does the...
  20. G

    Centripetal Force in an amusement park ride

    In an amusement park ride called The Roundup, passengers stand inside a 18.0 m-diameter rotating ring. After the ring has acquired sufficient speed, it tilts into a vertical plane. Suppose the ring rotates once every 4.90 s. and the rider's mass is 58.0 kg. A.) With how much force does the...
  21. H

    Centripetal acceleration automobile problem

    Homework Statement 6. A car of mass 1750 kg rounds a circular turn of radius of 21 m. The road is flat and the coefficient of kinetic friction between the tires and the road is 0.3, while the coefficient of static friction is 0.76. How fast can the car go without skidding? Homework...
  22. H

    Centripetal Force Problem: Calculating Speed of a Model Airplane on a String"

    Homework Statement A person is flying an 82 g model airplane in a horizontal circular path on the end of a string 11m long. The string is also horizontal (ideal situation). It exerts a force of 3.22N on the hand of the person holding it. What is the speed of the plane...
  23. L

    Centripetal Acceleration of North Pole

    Homework Statement Consider the radius of the Earth to be 6.38×106 m. What is the magnitude of the centripetal acceleration experienced by a person (a) at the equator and (b) at the North Pole due to the Earth's rotation? Homework Equations a = V^2 / r The Attempt at a Solution I...
  24. I

    Centripetal Force on an incline + Fricktion

    Homework Statement If a curve with a radius of 88m is perfectly banked for a car traveling 75kn/h, what must be the coefficient of static friction for a car not to skid when traveling at 95 km/hHomework Equations F=m(aR) F(Normal) x sin0 = m(v^2/r) The Attempt at a Solution I've asked my...
  25. T

    Centripetal and centrifual force reactions on objects?

    What would the centripetal and/or centrifual force be, on an object that was traveling in a 10mi circle at 18,000 mi/hr? OR how heavy would a person feel riding in a train traveling on the inside of a 10 mi round tube at 18,000 mi/hr?
  26. P

    Centripetal acceleration question

    Homework Statement Young David who slew Goliath experimented with slings before tackling the giant. He found that he could revolve a sling of length 0.800 m at the rate of 6.00 rev/s. If he increased the length to 1.100 m, he could revolve the sling only 4.00 times per second. (a) What is the...
  27. R

    Centripetal Acceleration and Tangential Acceleration problem driving me crazy

    A car is tested on a 230 m diameter track. If the car speeds up at a steady 1.2 m/s^2, how long after starting is the magnitude of its centripetal acceleration equal to the tangential acceleration? it seems simple, but i just can't seem to get it!... find: change in time when centripetal...
  28. C

    Centripetal Acceleration Space Shuttle Problem

    Homework Statement Suppose the space shuttle is in orbit 400 km from the Earth's surface, and circles the Earth about once every 90 minutes. Find the centripetal acceleration of the space shuttle in its orbit. Express your answer in terms of g, the gravitational accleration at the Earth's...
  29. C

    Centripetal force with circular motion

    This problem seems simple, but I can't get the answer: Homework Statement Tarzan tries to cross a river by swinging from one bank to the other on a vine that is 10.0 m long. His speed at the bottom of the swing is 8.0 m/s. Tarzan does not know that the vine has a breaking strength of 1000 N...
  30. Q

    Centripetal Force: Why Don't Planets Fall from Sun?

    Suppose if you're spinning a thread by your finger that has a cup attached to it at the other end. You would need to keep wobbling your finger or the cup would stop spinning, right? Then why doesn't the Sun wobble to keep the planets spinning around it? Or does the cup stop spinning because of...
  31. S

    Help with Centripetal Force question

    Homework Statement A 1000 kg sports car moving at 20 m/s crosses the rounded top of a hill (radius = 100m). Determine (a) the normal force on the car, (b) the normal force on the 70 kg driver, and (c) the car speed at which the normal force is zero. Homework Equations F = ma Fn = mg a...
  32. U

    Centripetal Force and maximum force

    Please help with the following problem: 1. A front-loading clothes washer has a horizontal drum that is thoroughly perforated with small holes. Assuming it to spin dry at 1 rotation per second, have a radius of 42 cm, and contain a 3.9 kg wet Teddy bear, what maximum force is exerted by the...
  33. H

    Is the Net Force at the Bottom of a Vertical Circle Greater or Lower Than MG?

    You are whirling a rubber stopper of mass something attached to a string in a vertical circle at high constant speed. At the bottom of the circle, the net force that causes acceleration is my answer was Vertically upward and greater in magnitude than MG. but the answer in the book says...
  34. X

    Determine the centripetal force

    Homework Statement Assume that the standard kilogram would weigh exactly 9.8 N at sea level on the Earth's equator if the Earth did not revolve about its axis. then take into account the fact that the Earth does rotate so that this mass moves in a circle of radius of 6.4 * 10^6 meters at a...
  35. P

    Finding centripetal acceleration

    1.The blade of a windshield wiper moves through an angle of 90 degrees in .28 . The tip of the blade moves on the arc of a circle that has a radius .76m. What is the magnitude of the centripetal acceleration at the tip of the blade. 2. Ac= v^2/r 3. okay, the accleration should...
  36. C

    Conservation of mechanical energy, centripetal acceleration, independence question

    Show that a roller coaster with a circular vertical loop. The difference in your apparent weight at the top of the circular loop and the bottom of the circular loop is 6 g's-that is, six times your weight. Ignore friction. Show also that as long as your speed is above the minimum needed, this...
  37. C

    Conservation of Mechanical Energy and Centripetal Acceleration Problem

    Show that a roller coaster with a circular vertical loop. The difference in your apparent weight at the top of the circular loop and the bottom of the circular loop is 6 g's-that is, six times your weight. Ignore friction. Show also that as long as your speed is above the minimum needed, this...
  38. V

    Calculating Maximum Speed and Acceleration for an Amusement Park Ride

    Homework Statement An amusement park ride carries riders in a horizontal circle with radius 5m. 1) If the centripetal acc. is limited to .4 g for safety, what is the max tangential speed? 2) If the tangential speed is doubled, what is the new acceleration? Homework Equations A=...
  39. G

    What is the Required Centripetal Acceleration for a Stone to Reach 25 Meters?

    Homework Statement You plan to throw stones by using a sling of length 1.3 m which you whirl over your head. Suppose you wish to throw a stone a distance of 25 m. What must be the centripetal acceleration of the stone just before its release if it is to reach this distance? Assume that the...
  40. K

    Centripetal Force (Loop the Loop)

    Homework Statement A pilot, whose mass is 78.0 kg, makes a loop-the-loop in a fast jet. Assume that the jet maintains a constant speed of 105 m/s and that the radius of the loop-the-loop is 0.562 km. What is the apparent weight that the pilot feels (i.e., the force with which the pilot presses...
  41. B

    Is My Calculation for Astronaut's Centripetal Acceleration Correct?

    Homework Statement Determine the rotation rate, in rev/s, required to give an astronaut a centripetal acc of 3g while in circular motion with radius 9.45 m. Homework Equations ac=v^2/r i did 3g=v^2/9.45 and got 1.76 then i used T=2pie(r)/v, put in T=2pie(9.45)/1.76 The...
  42. F

    Exploring Coriolis vs Centripetal Acceleration

    according to the figure attached below , do we have a coriolis acceleration on the slider and why ? why can't we say that it is a centripital acceleration ? I want to know the difference between coriolis accelration and centrepetal acceleration , cause As I know , coriollis...
  43. S

    Centripetal Force and Gravity: Exploring the Equator Paradox

    I was learning a bit of centrifugal/centripetal forces, and then I asked myself. If at the equator, the Earth rotates at about 1,700 kilometers per hour, then why don't we go flying outside the Earth due to the absence of centripetal forces. And if the gravity is enough to keep us on Earth, then...
  44. N

    Centripetal force on a stunt pilot

    A stunt pilot who has been diving vertically at 150m/s pulls out to dive into a circle in the vertical plane. a)What is the minimum radius of the circle, if the force on the pilot is not to exceed 6g. b)If the pilot has a mass of 80kg, what is the apparent weight of the pilot at the lowest...
  45. H

    Just started Centripetal Force

    ok the textbook says Centripetal Force always points towards the centre of circle as well as the Centripetal acceleration. But Why? Also I was given a diagram in the textbook like the one below. I don't understand why Fc = the friction force...
  46. K

    Expressing centripetal action with variables

    Homework Statement There is a string of length L dropped through a spool of thread. 10 paper clips are tied to each end and one end is twirled so that one bunch of clips moves in a horizontal circle at speed v while the other hangs vertically. Neglecting friction, write an expression: a) for...
  47. L

    Centripetal force vs. weight

    I am forming a concrete utility pole centripetaly in the mould (lathe). I need to have it form with an aperature(box shaped hole). I need to place a box to form the hole for the aperature and it needs to be of proper weight. the weight the concrete would of been had there been no aperture. It is...
  48. A

    Slight confusion about centripetal acceleration

    I just read in my book that the farther you are from the axis of rotation the greater the centripetal acceleration. But when dealing with circular motion the centripetal acceleration decreases as you increase the radius. Am I missing something? Or did I just confuse 2 different things? Thanks...
  49. T

    Centripetal force for an electron

    In a few chemistry books/resources I've seen the Bohr model of the atom is developed equating the electrostatic force to a centripetal force. Yet these sources also depict the centripetal force as being directed outward, away from the nucleus. (a single proton for the H atom) One even called it...
  50. G

    Calculating Maximum Speed on Bike Curve: Centripetal Force

    1. What is the maximum speed with which a bike can move at a curve, and on which angle from the vertical should he turn, so that he doesn't fall off the road, if the coefficient of friction is 0,4 and the radius of the curve is 100m? Now, I easily calculated the maximum speed by equating the...
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