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. E

    How Fast Must a Car Go to Clear a 12m Loop and What Are the Max G-Forces?

    1. So the loop is known to be 12m in diameter (6m radius). Assume the car weighs 1250kg - how fast must the car go to clear the loop, and what will be its max G-forces endured? This was the question, which I have broken into 3 sections: a) Velocity at top of loop (done) b) Velocity at start of...
  2. J

    Find period from centripetal motion that provides its own gravity

    Homework Statement The cylindrical space station, d = 280m in diameter, rotates in order to provide artificial gravity of g for the occupants. How much time does the station take to complete one rotation? Homework Equations velocity= (2*pi*r)/period acceleration = v^2/r The Attempt at a...
  3. R

    Tangential and centripetal acceleration

    Hello. Sorry for this very silly question, but I struggled myself too long on this (it was on the test and fortunataly I could answer correctly, but have not understood how to solve that). I know a particle, in a certain instant, has position ##(x_0,y_0,z_0)## I know the velocity magnitude...
  4. S

    Centripetal Force on a banked road

    Homework Statement 50.5 m radius 19 m/s speed µ = 0.2 acceleration due to gravity is 9.8 m/s2 At what angle θ should it be banked for maximum control of the racing car? Homework Equations sum of total forces=0? The Attempt at a Solution N*cosθ=mg N*sinθ-mgµ=(mv^2)/r mg*tanθ-mgµ=(mv^2)/r...
  5. J

    Centripetal force involved with a pulley system

    Homework Statement If you have a motor pulley and a drum pulley connected by a belt then how do you explain why the belt can sometimes slip if the washing machine is rotating too fast? Homework Equations The Attempt at a Solution I know that the answer involves the tension of the belt being...
  6. TheExibo

    Calculating Jet Speed in Vertical Loop: Centripetal Force Question 1 Explained

    1. A jet pilot feels 5.00 times her normal weight at the bottom of a vertical loop. The loop has a radius of 1.50 km. What is the speed of the jet at the bottom of the loop?2. F(centripetal)=(mv^2)/r3. The problem I'm having is with this equation that I've made based on the equation...
  7. X

    Centripetal force stunt driver problem

    Homework Statement A stunt driver for a movie needs to make a 2545kg car skid on a large, flat, parking lot surface. The force of friction between the tires and the concrete surface is 1.75x10^4N and he is driving at a speed of 24m/s. As he turns more sharply, what radius of curvature will he...
  8. P

    Torque vs Centripetal Force: What's the Difference?

    Torque causes a system to rotate about its axis while centripetal force causes a system to rotate about the axis of the separate system that exerted the centripetal force. So does this mean that torque specifically causes rotation and centripetal force causes revolution?
  9. R

    Understanding Centripetal Force & Friction

    So I know for a mass m with velocity v to travel in a circular motion, there has to be a centripetal force towards the center, but I'm having trouble intuitively visualizing why friction is directed towards the center? The way I see it, is for the car to turn , say left, the wheels rotate to...
  10. K

    Calculating Centripetal Force: Diagramming and Solving for X and Y Forces

    How would you go about proving that centripetal F=(mv^2)/r by diagramming and solving for the magnitude of the forces in the x and y direction? For example, suppose I wanted to calculate the work done in the radial direction by centripetal force.
  11. B

    Centripetal Acceleration of car

    Homework Statement Two cars drive around in circles at constant speeds. Car B's circle is twice as large as car A's, but its centripetal acceleration is three times as large. How many times faster is car B driving than car A? Homework Equations I'm trying to use a=(v^2/r) for centripetal...
  12. M

    Centripetal force apparatus lab

    Actually, I am going to do a centripetal force apparatus lab tmr morning. Here I get some pre-lab questions. In this lab, we are going to use economy force sensor (as I know there are 2 types, but it doesn't matter). There is one question related to this sensor... It says "The 'Tare' button on...
  13. A

    What is the Centripetal Acceleration Problem Solution?

    Homework Statement http://puu.sh/c0p5S/2fb2185acf.png Homework Equations I think a relevant eqn would be v=wr. The Attempt at a Solution I think answer is option A since Va/Vb=WRa/WRb. Is it correct? if not what is the right answer?
  14. P

    Centripetal acceleration of fairgrounds ride

    A fairgrounds ride spins its occupants inside a flying-saucer-shaped container. If the horizontal circular path the riders follow has a 8.00 m radius, at how many revolutions per minute will the riders be subjected to a centripetal acceleration 2.60 times that of gravity?
  15. T

    Vertical and horizontal circular motion: How to identify the centripetal force?

    I made notes on this in class, but I did not understand everything about it. So, what I know is that vertical motion is when the object goes around in a circle like this: And horizontal I guess it is like this: But then I am very confused regarding what my teacher told me for horizontal...
  16. Z

    Centripetal force of a ball swinging

    (Look at attached pic) The red ball is attached to a string which is being spun in a vertical circle. The downwards force is gravity and the other green one is the tension force. The blue is the sum of the green vectors. It is the centripetal force because it's the net force (and thus is equal...
  17. L

    Is Centripetal Force Affected by the Earth's Rotation?

    Supposed that a man is standing on the edge of a spinning merry-go-round which rotates at an constant angular speed with respect to a stationary fame of reference(the ground), there will be a centripetal force pulling him toward the centre of the marry-go-round and prevents him from sliding off...
  18. R

    Centripetal Acceleration along a curve

    I've spent hours on this question: A truck of mass 4500 kg is traveling in a fog due north at 20 m/s. Suddenly, at point A, the driver notices a wall straight ahead. He makes a sharp right turn along path AB, which is one-quarter of a circle of 50 m radius. He does this without any change in...
  19. D

    Centripetal Acceleration/Gravity Problem

    Homework Statement A circular "space hotel" in orbit around the Earth has a diameter of 355m. In order to produce "fake gravity" along the outer rim, it is desired to rotate it at a speed that will produce a centripetal acceleration of 9.81m/s^2. Note the geometry: people walking on the inside...
  20. J

    Centripetal force and water in a Bucket

    Homework Statement To explain why water falls out of a bucket when it is not being swung fast enoughHomework Equations a = mv^2/r The Attempt at a Solution I have had a look on previous threads and nearly get it but still a bit confused. When the bucket is upside down and the required...
  21. 2

    Can you have angular acceleration without centripetal acceleration?

    Homework Statement My guess is no because if you have a ball on a string, for there to be angular acceleration, the angular velocity must increase so you need an increasing tangential speed, so your centripetal acceleration must increase (α=v2/r)... but I'm not sure. One other question...
  22. Greg Bernhardt

    Understanding Centripetal Force: Definition, Equations & Free Body Diagrams

    Definition/Summary Centripetal force is not a separate force. It is only an alternative name for the radially inward component of tension or friction or other force or forces on a body. In a free body diagram, centripetal force should never be mentioned by name (it should be called...
  23. Greg Bernhardt

    What is centripetal acceleration

    Definition/Summary Centripetal acceleration of something moving in a circle is the component of its acceleration towards the centre of the circle. Equations a_c=-\omega^2 r a_c=-\frac{v^2}{r} These apply if m and r are fixed, and even if \omega and v are not. The minus sign...
  24. G

    What is the difference between centrifugal and centripetal forces?

    Hi all. This is not a homework question, I'm 33 and far away from homework. It is just a personal doubt. I've read a lot about these forces, even some answers from these forums but still can't make something out of them. What I've read: *Centripetal: a force that makes objects attracted to a...
  25. BrainMan

    Centripetal force problem with tension

    Homework Statement In a test of machine-part reliability, a specimen of mass m is swung in a vertical circle of constant radius .75 m. When the object is at the bottom the circular path, the tension in the supporting wire is found to be six times the weight of the object. Determine the...
  26. B

    Centripetal Force, Gravity and Normal

    Homework Statement Homework Equations F_{c} = \frac{mv^{2}}{r} The Attempt at a Solution I think the normal force would be the magnitude of vector sum of centripetal force and gravitational force. So I did: N = \sqrt{(\frac{mv^{2}}{r})^{2} + (mg)^{2}} However, it isn't one...
  27. BrainMan

    Another centripetal force problem

    A stuntman swings from the end of a 4 m long rope along the arc of a circle. If his mass is 70 kg, find the tension in the rope required to make him follow his circular path at (a) the beginning of his motion, assuming he starts when the rope is horizontal, (b) at a height of 1.5 above the...
  28. A

    Centripetal vs Radial acceleration

    I am reading introductory physics from Serway. Where they say if a_r is radial acceleration and a_c is centripetal acceleration then a_c = v^2/r and a_r = -a_c = - v^2/r But aren't the radial and centripetal acceleration same (correct me if I am wrong)? Why is there a minus sign? The...
  29. BrainMan

    Solve for Maximum Speed of a Car on a Circular Turn | Centripetal Force Problem

    Homework Statement A car of mass 2000 kg rounds a circular turn of radius 20 m. If the road is flat and the coefficient of friction is 0.7 between the tires and road, how fast can the car go without skidding? Homework Equations Fc = m(v2/r) The Attempt at a Solution I tried to find...
  30. BrainMan

    Another centripetal Acceleration problem

    Homework Statement (a) What is the tangential acceleration of a bug on the rim of a 78 rpm record 10 in. in diameter if the record moves from rest to its final angular velocity in 3 s? (b) When the record is at its final speed, what is the tangential velocity of the bug? Its tangential...
  31. BrainMan

    Find the centripetal acceleration of the moon

    Homework Statement The moon circles the Earth with a period of 27.3 days at a distance of about 250000 mi. Find the centripetal acceleration of the moon.Homework Equations ac = v2/r The Attempt at a Solution I first found the velocity by converting 2 pi radians per 27.3 days to radians per...
  32. Nathanael

    Uniform Circular Motion and Centripetal Acceleration

    In introductory physics books (or at least mine) it limits the equation a_c=\frac{v^2}{r} to the sitaution where the speed around the circular path is constant. It enforces the idea that the speed is CONSTANT. But wouldn't the equation also apply to non-constant speeds? (a_c would just...
  33. M

    Tension in the thread: Centripetal Force in the Vertical plane

    I get the theory: Fc = Ft + Fg Uniform circular motion, in the vertical plane. Fc = net force = centripetal force Ft = force of tension in the string Fg = force of gravity so at the top, with vector addition: Ft = Fc- Fg And if we define 'up' as positive, then should the equation look like...
  34. Maxo

    Centripetal acceleration and tangential acceleration

    When having a circular acceleration motion, we have both tangential acceleration and centripetal acceleration. The tangential acceleration is aT=r*α where α=1/2*(ωf-ω0). So we can see tha aT is dependant on both the initial angular velocity ω0 and the final ωf). For centripetal...
  35. adjacent

    Centripetal and centrifugal forces

    Homework Statement A space station is connected to a box(50kg) with a super strong string(1m) and it is rotating which makes the box rotate at a speed of 10m/s. I am inside the box. Find the force the box exerts on me. Homework Equations ##F=m\frac{v^2}{r}##The Attempt at a Solution I found...
  36. D

    Centripetal acceleration speeding car problem

    Homework Statement A car is traveling round a bend which is banked at an angle of 30 to the horizontal. The bend is assumed to be in the shape of an arc of a circle of radius 80m. the surface of the road is rough and the coefficient of friction between the tyres of the and the surface of the...
  37. C

    Centripetal acceleration acting on a parcel

    Homework Statement A parcel sits on a seat angled θ to the horizontal. The car is traveling along a local radius of curvature of 80m and is traveling 20m/s at the dip. For what value of theta will the parcel not slip? Will someone check that my force diagram is correct? Thanks, cmcd...
  38. mcastillo356

    I don't distinguish gravity and centripetal acceleration

    Homework Statement There is a famous thought experiment that Newton put forward: imagine a very tall mountain where there is no air friction. We'll put a cannon on top of this mountain, and we'll fire cannon balls put of with greater and greater velocities in the horizontal direction. Let's...
  39. D

    Centripetal force demo dishonesty

    I find physics classroom demonstrations of centripetal force dishonest, they often resort to trickery to demonstrate this apparent "inward pull" on a body in circular motion. Two examples follow 1, Centripetal force "pulling" a candle flame towards the center of a spinning turntable 2...
  40. A

    Uniform Circular Motion and Centripetal Force

    Hey guys, first post here! Hoping to get a little help. Homework Statement You are a traffic safety engineer in charge of determining safe speeds for roads. A particular banked curve has a radius of 11.0 meters and is banked at an angle of 8.00°. The coefficient of static friction between...
  41. M

    Centripetal Force & Tension Homework Solution

    Homework Statement A 1.5 kg mass tied to the roof rotates with constant speed in a horizontal circle. The string makes an angle of 30 deg to the vertical. a) determine the velocity , the centripetal acceleration and the centripetal force on the mass. b) determine the tension in the...
  42. S

    Centripetal Force String Tension

    Homework Statement Two masses M of the same amount are tied to two stings of length L and 2L. If both masses are swung in unison faster and faster, which string will break first? Homework Equations The formula I've been using is Tension = mv^2/r. The Attempt at a Solution My...
  43. jdawg

    Creating Artificial Gravity in Space: Using Centripetal Force on a Space Station

    Homework Statement Could centripetal force be used to create a sort of artificial gravity aboard the space station? If so, how would you go about this? Homework Equations The Attempt at a Solution At first I wanted to say yes, but how fast would the space station have to rotate...
  44. G

    Centripetal acceleration and circular motion

    My question is about the centripetal acceleration formula |a| = ω^2*r. If we keep the angular speed constant then why does increasing the radius increase the centripetal acceleration? I don't find this intuitive because the velocity vector is being turned by the same amount each second, if ω is...
  45. T

    Centripetal Acceleration Question

    An object weighing 4 Newtons swings on the end of a string as a simple pendulum. At the bottom the swing, the tension in the string is 6 Newtons. What is the magnitude of the centripetal acceleration of the object at the bottom of the swing.Centripetal Acc. = v^2/r Sum of forces =...
  46. K

    Centripetal Acceleration Problem

    Homework Statement A centrifuge rotates at 12000rpm, what is the radians per second? If the radius of the centrifuge is 150mm, what is the centripetal acceleration? Homework Equations Angular Velocity: ω = Δθ/Δt (maybe, not sure) Centripetal Acceleration: a = v2 / r The Attempt at a...
  47. T

    Two blocks stacked centripetal motion

    Homework Statement Mass 1(2.0kg) sits on top of mass 2(5 kg), which rests on a frictionless surface. The coefficient of static friction between mass 1 and 2 is 0.30. A string of length 5.0m is tied to mass 2, and both masses are swung around in a horizontal circle. Calculate a) the max speed...
  48. K

    Centripetal acceleration and radius

    I am curious how to tell how centripetal accel. changes with radius since there are two equations I can look at a = v2/r or a=wr I read on a thread that if v is constant then use the top equation and if w is constant then use the bottom equation. Is this true? If so, can you please give...
  49. S

    Centripetal Acceleration Quick Question

    Homework Statement A bridge over a small river has a roadway which is in the shape of an arch having radius of curvature of 41 m. What is the maximum speed at which an automobile can travel across the bridge without leaving the bridge? Homework Equations Fc = (mv^2)/r Fg= mg The Attempt...
  50. S

    Centripetal Force of satellites

    Homework Statement One of Saturn's satellites travels in a circular orbit at a velocity of 19481 m/s. Saturn's mass is 5.69x10^26 kg. What is the radius of the satellites orbit? Homework Equations Fg = (G * m1 * m2) / (r^2) Fc = (m*v^2)/(r) The Attempt at a Solution The...
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