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. M

    Centripetal Force Lab Questions?

    So we did a lab in physics today and it was a contraption where we had a stopper on one get of the string, and weights on the other, and we spun the stopper around, and there's 4 questions that i don't under stand, so if you could help me with this, and please explain as i want to know how to do...
  2. M

    Centripetal Force Lab Questions?

    So we did a lab in physics today and it was a contraption where we had a stopper on one get of the string, and weights on the other, and we spun the stopper around, and there's 4 questions that i don't under stand, so if you could help me with this, and please explain as i want to know how to do...
  3. F

    Tensions and centripetal acceleration

    Homework Statement An object of mass m1 of 4.00kg is tied to an object of mass m2 of 3.00kg with a string of length 0.5m. The combination is then swung in a verticular circular path on a second string of length 4.00m. The two strings are always colinear (they are on the same line). At the...
  4. P

    Serious problem with centripetal force

    Homework Statement The soluble problem We have a disc, horisontal, which is rotating 0.5 revolutions per second. A block is placed on this disc with the mass 0.6 kg and 0.2 meters from the shaft. First, I convert 0.5 rates per second to T = 2 seconds. w = 2∏/2 --> w = ∏ --> m = 0.6 kg -->...
  5. M

    Centripetal acceleration graph

    Mg=[1600∏2m(L+a)(1/t2)]- b M is the mass of the slotted weight g is the gravitational force m is the mass of the sticky tape L is the length of the nylon thread measured from the end of the plastic tube to the sticky tape t is the time for 20 revolutions of the sticky tape a and b are...
  6. P

    Centripetal Force - My conclusions are correct?

    Homework Statement I'm supposed to give the three forces acting on the basket on a carousel. Homework Equations Principly not for this task. The Attempt at a Solution When I look at the forces on the baskets on the carousel in constant rotation, I can point out the three...
  7. S

    What Are the Equations for Calculating Centripetal Acceleration?

    The radius of the Earth's orbit about the sun is about 1.5x10^11m. The mass of the Earth is 5.98x^10^24kg Equations: ac= v^2/r ac=4∏^2/r v=2∏r/T I could not figure out what to do so i could not attempt it
  8. M

    Centripetal Force and ball of string

    Hello, could someone look over my answer? I am not very confident I did the problem correctly. Homework Statement A 76-kg ball is tied to one end of a massless string of length The other end of the string is tied to a nail in the center of a table. The ball is set into uniform circular...
  9. T

    Centripetal Acceleration HELP. Is it challenging? Well come find out

    1. An athlete whirls a 7.48 kg hammer tied to the end of a 1.4 m chain in a horizontal circle. The hammer moves at the rate of 1.76 rev/s. What is the centripetal acceleration of the hammer? Assume his arm length is included in the length given for the chain. Answer in units of m/s...
  10. E

    Centrifugal Force, Centripetal Force, and Space

    I've got a weekly physics assignment, and I've been racking my brain on it. Any input on the accuracy of my response, what I could do to improve it, and where I may have gone wrong? Homework Statement Some years ago, a newspaper story contained the following statement" "The space shuttle...
  11. P

    Centripetal Acceleration of rope and bucket

    Homework Statement A bucket of mass 2.00 kg is whirled in a vertical circle of radius 1.10 m. At the lowest point of its motion the tension in the rope supporting the bucket is 25.0 N. (a) Find the speed of the bucket. (b) How fast must the bucket move at the top of the circle so that the...
  12. M

    Rotating Spacecraft Causing 'Artificial Gravity' via Centripetal Force

    How is this possible? The reason spinning a bucket of water upside down keeps the water inside the bucket is because you're applying force and accelerating the bucket. But in space, there is nothing 'accelerating' the rotation of a spacecraft , it is merely in continuous Newtonian motion...
  13. M

    Centripetal acceleration of the satellite?

    Homework Statement An Earth satellite moves in a circular orbit 790 km above the Earth's surface. The period of the motion is 100.5 min. (a) What is the speed of the satellite? (b) What is the magnitude of the centripetal acceleration of the satellite?Homework Equations a= v2 / r T = (2 Pi...
  14. E

    Radius of centripetal force when on an angle.

    http://puu.sh/4IjIT.png I don't quite understand why this is correct. My initial try was this... (the only difference is at the end, bolded) r = 0.154m period = 0.426s rev per second = 1/0.426s w = 2*pi*(1/0.426) mg = Fn*cosx Fn = mg/cosx Fc = Fn*sinx = mg/cosx = mg*tanx...
  15. G

    Centripetal acceleration vector

    Purely mathematically, how does the expression for the centripetal acceleration a=v^2/R give information about the direction of the acceleration vector? I don't seem to notice any indication that the acceleration vector should be perpendicular to the velocity, or pointing towards the center...
  16. P

    Centripetal force problems for dynamics

    Centripetal force problems for dynamics :) Homework Statement I have two questions! 1. You are driving at a speed of 60.0km/h around a turn with a radius of 75m. The coefficient of friction between the tires and the road is 0.85. a. After traveling 20° around the turn, you hit a...
  17. A

    Physics centripetal acceleration/ mass

    Homework Statement A moon orbits a planet of unknown mass with a period of 1.8 days. If the radius of the moon's orbit is 420,000,000 meters, find the mass of the planet. Homework Equations For the speed of the moon I got: v=2 x pie x r / v 2 x pie x 420000000 / v = 1.8 days or...
  18. L

    Centripetal or centrifugal? The Physics of Water Escape in a Washing Machine

    Homework Statement 13. Why does the water in a washing machine escape through the little holes during the spin cycle? a The water is flung out of the clothes by the centripetal force. b The water is flung out of the washer by the centrifugal force. c The water is sucked out of the...
  19. H

    Centripetal Acceleration of amusement ride

    Homework Statement An amusement ride with a radius of 4.8m allows riders to experience 4.3g's of centripetal acceleration. What is the frequency of the ride? Homework Equations a_{c}= 4∏^{2}r∫^{2} The Attempt at a Solution a_{c}=4.3 r=4.8m ∫=? I keep getting a weird...
  20. X

    How is it possible that friction = centripetal force for turns?

    So, I am confused. If a car is driving on a flat surface and it turns, it experiences centripetal force. Apparently, the friction of the bike is equal to this force. This doesn't make sense to me. I've drawn a few forces on an example picture here: The car is going straight, and Fa is...
  21. X

    Physics turns and centripetal force on flat roads

    I am confused about this. I learned that the frictional force is pointing towards the center of the circle in circular motion (on a flat road) due to the tires. The thing is, I don't understand what the result of this friction is. The road is flat, and the motion of the car is straight...
  22. K

    Tangential and Centripetal Acceleration

    Homework Statement A bike is travel up and over a hill with a radius at the top of the hill of 10 meters. The bike is traveling at 10 m/s at position A and 5 m/s at position. (and the problem comes with a picture showing an angle of 60* between point A and B. a. Determine the average...
  23. Philosophaie

    Centripetal Acceleration of an Ellipse

    The centripetal acceleration of a circle is: a_c = \frac{v^2}{r} * u_n. The acceleration of an ellipse is different. It increases from from apoapsis to periapsis as the position changes from furthest point in the orbit to the closest. Then decreases from from periapsis to apoapsis as the...
  24. F

    Finding centripetal acceleration and velocity

    Homework Statement a) After take-off an airplane takes a U-turn tilting the plane 45 degrees to one side. The speed and height is constant. Find the centripetal acceleration. Mass: 79010 kg Engine Fmax: 2x 121.4 kN b) The U-turn took 47 seconds. What is the velocity in km/h of the airplane...
  25. PsychonautQQ

    Inelastic Momentum / Centripetal force problem

    Homework Statement A small wooden block with mass .8kg is suspeded from the lower end of a light cord that is 1.6m long. The block is initially at rest. A bullet with mass 12g is fired at the block with a horizontal velocity vi. The bullet strikes the block and becomes embedded in it. After...
  26. O

    Calculating Centripetal Force for Circular Motion: Tips and Tricks

    Hello, I'm having trouble with solving for the centripetal force. Some questions in my textbook don't give the velocity and radius, so the centripetal force is a bit harder to calculate. There are three main scenarios which I am having trouble with: [1] A girl has a ball in her hand...
  27. O

    Centripetal Acceleration definition help

    Hello, my textbook says that the magnitude of centripetal acceleration is equal to the sum of the forces acting on that object. (this is in regard to an object in a circular path, by a string. See...
  28. M

    Electric Charges Causing Centripetal Motion

    Homework Statement A particle of charge Q is fixed at the origin of an xy coordinate system. At t = 0 a particle (m = 0.671 g, q = 5.90 µC is located on the x-axis at x = 15.6 cm, moving with a speed of 54.4 m/s in the positive y direction. For what value of Q (in μC) will the moving particle...
  29. S

    Extreme Confusion of centripetal acceleration force and normal force

    Hi guys, first off, thanks for answering my previous question... Now here's another one. I got confused by my school's homework a bit...so there's a car that travels over a humpback bridge with a radius of 45m, so basically it's a semicircle bridge, and so I'm supposed to calculate the...
  30. K

    Conceptual centripetal problem of a spinning ball attached to a string

    Homework Statement If you swing a ball in a vertical circle using a thin string, at the bottom of the circle the tension in the string must be greater than the ball's weight. True or false? Homework Equations F = mvv/r F = mg The Attempt at a Solution The correct answer, it says...
  31. K

    Centripetal Force of an amusement park ride

    Homework Statement In an amusement park ride, passengers stand inside an 8m radius cylinder. Initially, the cylinder rotates with its axis oriented along the vertical. After the cylinder has acquired sufficient speed, it tilts into a vertical plane, that is, the axis tilts into the horizontal...
  32. L

    Archived Centripetal force and Coriolis force?

    Homework Statement Suppose that you are on a rotating platform, going around with frequency w a distance r from the center. Suppose that you are watching an object that moves in a straight line. Produce an animation that shows the position of the object from your perspective. Does this...
  33. N

    Centrifugal and centripetal force

    There is a grass planted in a container which spins. Will the grass grow from the center of the container or will it bend towards the center. These are provided answers: This is a question in my book and there it is stated that it will bend towards the center(A answer) but it is not...
  34. adjacent

    Centripetal Force and radius of the circle

    When the radius of the circle decrease the object moves faster(With the same force) I believe this is a misconception .In common sense the object revolves around more,This leads us to think that it is moving fast but actually the object moves the same distance.Am I right?
  35. E

    Little confusion regarding centripetal force in vertical circle

    consider a pendulum. The mass 'm' is hung and now we are interested in finding the velocity so that it completes one circle. Clearly we can do it easily by conserving energy. Now my problem is with the top most point. Clearly the tension is minimum at this point so that string becomes slack...
  36. sa1988

    Rigid body, circular motion - centripetal acceleration

    Hi all, new user here and straight in with a question to help me understand something. Not sure if I'm in the right sub-forum but oh well. Regarding circular motion and centripetal acceleration, we're given the classic example of a cyclist leaning into a corner to create a general equilibrium...
  37. B

    Centripetal force/friction on a car in circular path

    I've read so much stuff on the internet including other threads on the forum but am still confused. When a car is making a turn on a level road, WHY does the static friction point inward? From what I've learned the direction of static friction points in the direction opposing movement but the...
  38. S

    Centripetal force carousel angle

    Hello everybody, i have got a question about the concept of centripetal force in general. Imagine a gondula of a carousel that has just started to rotate. Each gondula moves away from the center of the circular motion and forms an angle with the string. What would be the correct physical...
  39. Q

    Using Centripetal Forces to find the radius of a circle

    Homework Statement A 100g (0.1kg) rock is attatched to a 1.0m rope and spun around in a circle with a period of rotation of 1.0s. What is the Radius of the circle that it forms? Homework Equations Fc = (mV^2) / r V= (2∏r/T) LCosθ = r The Attempt at a Solution Im quite stick...
  40. D

    Does the gravity we feel equal G(M/r^2) - our centripetal acceleration

    We all know that something traveling in cicular motion at a constant speed has a centripetal acceleration towards the axis of rotation. I suppose this means we (travelling around the axis of rotation of the earth) also require a centripetal acceleration. This can be provided by gravity which is...
  41. N

    Draw a free body diagram of each object in centripetal acceleration

    Homework Statement Draw a free body diagram of each object in Italics, that is in centripetal acceleration, and name the force causing this centripetal acceleration. a. Moon in circular orbit around Earth. b. Electron in circular orbit around nucleus of atom . c. Snowboarder slides over...
  42. A

    Finding centripetal force of an object

    this is a question i have to do over the holidays and have no clue of how to do it. i cannot access our school email in which i have the worked solutions to all the questions. A ball is tied to a string and whirled in a horizontal circle radius of 2.0m. The string makes an angle of 10...
  43. S

    How does centripetal acceleration can cancel out gravity?

    Homework Statement I know the answer and how to get it, but it doesn't make sense because ac points down and so does g. So why do they seem to cancel each other out? What is the minimum constant speed a motorbiker needs in order to make it around a vertical loop with a radius of 3 meters...
  44. M

    Is tangential force the same as centripetal force?

    Homework Statement Rotor blades attatched to a disc rotate. The rotor blades rotate at a speed of 15574rpm. The blades are 220mm from the centre of the disc. These blades are attatched to a disc that is 400mm in diameter. A force of 8kN/rad acts upon the blades and 600N/rad. (see...
  45. totallyclone

    Using a stone to hunt down an animal with Centripetal Forces

    Homework Statement A bushman wants to hunt down a kangaroo so he uses a vine which is 2.0m long with a rock tied to the end of it. The bushman holds the other hand above his head which is 2.0m above the ground. The kangaroo observes that when the angle with the vine and vertical reaches 60°...
  46. O

    Centripetal force. Radius is not given. Find tension in each support

    There is this problem that I have been trying to do but I just cannot understand how to approach it. I have been doing centripetal problems for hours so maybe I am just tired. The thing is that I do not see an equation I can use to cancel out radius since the radius is not given. I have...
  47. G

    Centripetal force, enough information?

    Homework Statement We have a carousel that completes a revolution in 4,0 s. The radius of the carousel disk is 0,8 m and the length of the (massless) rope is 1m. A horsey or whatever weighing 1 kg is hanging from the rope. Can we from this information extract the velocity of the horsey...
  48. F

    When to use centripetal vs. radial acceleration

    My question is more general than anything. When do I use centripetal acceleration vs. radial acceleration. The solutions in my physics book define a in polar coordinates as positive (v^2)/r. However, my professor uses -((v^2)/r). When do I know when to use each respective form? Thanks
  49. R

    Centripetal Force and Uniform Circular Acceleration

    I am in need for some help for a lab report. The issue has happened because there is a lab of 20 students that is being led by a recently retired NASA physicist trying to lead a team of graduate student (or camel jockeys as he puts it) and the lab instructions are being botched horribly...
  50. X

    Centripetal force, this is confusing. Why?

    Homework Statement Someone takes a rock and ties it to a string, and then starts swinging the rock around in a vertical circle. The centripetal force should be... Fc = Fg + FtIt's clear that the book sets Ft=0... but why? Can someone explain this?Homework Equations Fc = m * ac ac = v^2/rThe...
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