What is Centripetal acceleration: Definition and 411 Discussions

In mechanics, acceleration is the rate of change of the velocity of an object with respect to time.
Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by the orientation of the net force acting on that object. The magnitude of an object's acceleration, as described by Newton's Second Law, is the combined effect of two causes:

the net balance of all external forces acting onto that object — magnitude is directly proportional to this net resulting force;
that object's mass, depending on the materials out of which it is made — magnitude is inversely proportional to the object's mass.The SI unit for acceleration is metre per second squared (m⋅s−2,






m

s

2







{\displaystyle {\tfrac {\operatorname {m} }{\operatorname {s} ^{2}}}}
).
For example, when a vehicle starts from a standstill (zero velocity, in an inertial frame of reference) and travels in a straight line at increasing speeds, it is accelerating in the direction of travel. If the vehicle turns, an acceleration occurs toward the new direction and changes its motion vector. The acceleration of the vehicle in its current direction of motion is called a linear (or tangential during circular motions) acceleration, the reaction to which the passengers on board experience as a force pushing them back into their seats. When changing direction, the effecting acceleration is called radial (or orthogonal during circular motions) acceleration, the reaction to which the passengers experience as a centrifugal force. If the speed of the vehicle decreases, this is an acceleration in the opposite direction and mathematically a negative, sometimes called deceleration, and passengers experience the reaction to deceleration as an inertial force pushing them forward. Such negative accelerations are often achieved by retrorocket burning in spacecraft. Both acceleration and deceleration are treated the same, they are both changes in velocity. Each of these accelerations (tangential, radial, deceleration) is felt by passengers until their relative (differential) velocity are neutralized in reference to the vehicle.

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  1. M

    Why Does Apparent Weight Change on a Ferris Wheel?

    Homework Statement Explain the shift in apparent weight at the top and bottom of a ferris wheel. Homework Equations The Attempt at a Solution I am just not able to grasp centripetal acceleration. I understand at the top point, gravity AND centripetal acceleration are downwards...
  2. C

    Centripetal acceleration where to start

    Homework Statement A car travels at a constant speed around a circular track whose radius is 2.63 km. The car goes once around the track in 353 s. What is the magnitude of the centripetal acceleration of the car? Homework Equations A=V^2/r C=1/2(pi)R^2 The Attempt at a Solution...
  3. B

    Centripetal acceleration problem

    A small bug is sitting on the edge of a uniform disk of mass 2.5 kg and radius 20 cm initially at rest. There is a massless string wrapped around the disk and the coefficient of friction between the bug and the disk is u= 0.4. The string is then pulled with a constant tension of 4 N. a) What...
  4. G

    Centripetal acceleration at the ends of a rotating rod?

    Homework Statement Sorry, I don't have a picture, so I can only relate this in words, so I have to indirectly translate it to drawing: So you have a 0.15 m rod titled at a 45 degree angle above a horizontal , like this: \ Now rotate it some distance away from a vertical axis. The bottom of...
  5. A

    Calculating earth gravity by using centripetal acceleration

    Homework Statement I am asked to calculate the value of gravitational acceleration at Earth's surface given the following Moon's period around the Earth - 27 days 8 hours Moons orbit - 60.1 times the radius of Earth (6.38 x 10^6 m)Homework Equations Fc=(4*3.142mR)/T2 which works out to be...
  6. V

    Centripetal acceleration in a roller coaster loop

    Homework Statement I performed an experiment with a plastic tube and a ball. The tube was shaped into a roller coaster track with a circular vertical loop of diameter 0.12 m. I have to calculate the centripetal acceleration of the ball while in motion within the loop. I have only studied...
  7. C

    Centripetal acceleration - why?

    Just a general "why" question. Why does the centripetal acceleration increase when the radius decreases? This is not a homework question but rather something I'm trying to make sense of. I read that: "The centripetal acceleration has to continuously change the velocity vector back towards the...
  8. G

    What causes the centripetal acceleration of the earth?

    For a body to undergo uniform circular motion, a centripetal force which is perpendicular to the velocity at all times must be applied to the body. For the moon and the earth, the gravitational force exerted on the moon by the Earth causes the moon to move in a circle instead of continue on a...
  9. C

    What Causes the Centripetal Acceleration in Circular Motion?

    It seems that centripetal acceleration should be in the same direction as the velocity vector. Why is it directed into the center of the circle. I remember walter lewin talking about a marble inside a glass test tube. Imagine the marble inside of it and I swing the test tube like a baseball...
  10. M

    Multiple answers to this question? Centripetal acceleration

    Hi, I'm working on a paper about the problems with standardized testing. On a recent test that I took there was one problem that I thought could demonstrate one of the problems with standardized testing, multiple answers to a single question based on interpretation, and I thought I might use it...
  11. T

    Average centripetal acceleration

    I need to find the average centripetal acceleration, I know the equation is aR= v^2/r but I am not given the radius only speed and time
  12. D

    Changing factor of centripetal acceleration

    Homework Statement A particle moves in a circular path of radius r with speed v. It then increases its speed to 19v while traveling along the same circular path. By what factor has the centripetal acceleration of the particle changed? Homework Equations ac=v^2/r The Attempt at a...
  13. E

    Confused by radial vs. centripetal acceleration

    Hi I've been working through some examples from the course material we use in physics class, but one thing keeps confusing me: What is the difference between centripetal and radial acceleration? For instance, when we have a particle traveling in a circular path, the acceleration towards...
  14. A

    Two equations for centripetal acceleration

    My question is how can Ac (centripetal acceleration) be both inversely related to radius and directly related in two equations: 1) Ac = V2/r 2) Ac = 4pi2r/T2 In the first equation Ac is inversely proportional to radius in the second one Ac is directly proportional to radius. Why and how is...
  15. R

    What is centripetal acceleration?

    I'm having trouble grasping the concept of centripetal acceleration on circular motion. I understand angular velocity. From there what my books gives me is the centripetal accel formula. ac=(v^2)/R I don't notice any acceleration in a circular motion. Nothing's accelerating. What velocity is...
  16. T

    Can gravitational field strength equal the centripetal acceleration?

    As a homework question, it asks, "...if the Earth were rotating so fast that the objects at the equator were apparently weightless?" Somewhere, someone said that, quote: In order for the rotation of the Earth to cancel weight, the gravitational field strength should equal the centripetal...
  17. C

    Centripetal Acceleration metres per second squared

    Homework Statement What is the magnitude of the centripetal acceleration of a point on the circumference of a 0.32m radius bicycle wheel rotating at 22 rad/s ? Give your answer in metres per second squared Homework Equations To be honest I am stumped I have no idea The Attempt at...
  18. P

    Centripetal Acceleration Problem

    Homework Statement What is the centripetal acceleration of the Moon? The period of the Moon's orbit about the Earth is 27.3 days, measured with respect to the fixed stars. The radius of the Moon's orbit is RM = 3.85 · 108 m. Homework Equations a = V^2/R V = 2*pi*R/P The Attempt...
  19. S

    Two questions about centripetal acceleration,

    Homework Statement #1 The drawing shows a baggage carousel at an airport. Your suitcase has not slid all the way down the slope and is going around at a constant speed on a circle (r = 14.0 m) as the carousel turns. The coefficient of static friction between the suitcase and the carousel is...
  20. S

    Simple centripetal acceleration question

    Hello everyone When do you use -v^2/R instead of positive v^2/R for the acceleration in circular motion? Thanks. Stephen
  21. D

    Angles Transversed with Centripetal Acceleration

    Homework Statement Okay, so the problem is I need to find the radius of curvature for a proton moving through a uniform magnetic field with initial velocity v for some distance d and exiting at angle θ. I was able to get the correct answer; however, I think the apparent assumption made by the...
  22. N

    Deriving Max. Velocity for Banked Curve with Friction (Centripetal Acceleration)

    Homework Statement A circular curve of radius R in a new highway is designed so that a car traveling at speed v0 can negotiate the turn safely on glare ice (zero friction). If a car travels too slowly, then it will slip toward the center of the circle. If it travels too fast, then it will slip...
  23. S

    Tangental acceleration from given centripetal acceleration and a range of radii

    Hi, how can I determine the tangental acceleration of a circle needed to produce a given centripetal acceleration from a range of radii? For example, I would like to produce 9.81 m/s/s centripetal acceleration with a range of radii from 5km to 100km? All I really need is to figure out the...
  24. C

    Centripetal Acceleration and Satellite Question

    1. The astronaut orbiting the Earth in Figure P4.30 is preparing to dock with a Westar VI satellite. The satellite is in a circular orbit 600 km above the Earth's surface, where the free-fall acceleration is 8.21 m/s2. The radius of the Earth is 6400 km. a) Determine the speed of the...
  25. P

    Doubt with centripetal acceleration

    Good afternoon, For a body in a curvilinear motion moving with velocity \vec{v}, velocity can be divided into two components (see http://en.wikipedia.org/wiki/Angular_velocity#Two_dimensions" Wikipedia article): a component parallel to the position vector (the radius), which changes the...
  26. G

    Town clock seconds hand speed and centripetal acceleration

    1. (a)The speed of the tip of the minute hand on a town clock is 0.00136 m/s. What is the speed of the tip of the second hand of the same length? Answer in units of m/s. (b)What is the centripetal acceleration of the tip of the second hand? Answer in units of m/s2. Homework...
  27. R

    How Is the Total Acceleration of a Car Calculated in Circular Motion?

    A car starts from rest and travels along a circular path of radius 200 m. The magnitude of its velocity increases at a rate of 2 m/s After 10 s, what is the magnitude of the acceleration of the car (in m/s my attempt: v = 10*2 = 20m/s would the acceleration that the car's...
  28. M

    Centripetal acceleration using a sling

    Homework Statement You plan to throw stones by using a sling of length 1.6 m which you whirl over your head. Suppose you wish to throw a stone a distance of 32 m. What must be the centripetal acceleration of the stone just before its release if it is to reach this distance? Assume that the...
  29. Shackleford

    Kepler's Third Law and centripetal acceleration

    I'm not getting very far with these problems. Don't know what my problem is. Given a circular orbit, the centripetal acceleration is given by the gravitational force between the two stars. I chose the center to be halfway between the stars d/2...
  30. F

    Help with physics lab containing the centripetal acceleration law

    [b]1. The aim of the lab is to verify the centripetal acceleration law which states that acceleration is equal to the velocity squared divided by the radius. During the lab, we spun a string powered whirligig. There was a ball at the top, attached to string, the string was threaded through a...
  31. N

    Centripetal acceleration blood plasma problem

    Homework Statement From Tipler's Physics for Scientists and Engineers(the latest edition) 71.Human blood contains plasma, platelets, and blood cells. To separate the plasma from other components, centrifugation is used. Effective centrifugation requires subjecting blood to an acceleration...
  32. S

    How Do You Calculate Total Acceleration of a Particle on a Circular Path?

    Homework Statement A particle starts from rest at t=0 s. It moves along a circular path of radius 18m and has an acceleration component along its path of 4.3m/s^2. What is the magnitude of the acceleration when t=3 s? Homework Equations N/A The Attempt at a Solution I am...
  33. M

    What is its centripetal acceleration?

    Homework Statement (a) What is the tangential acceleration of a bug on the rim of a 8.0 in. diameter disk if the disk moves from rest to an angular speed of 77 rev/min in 3.0 s? (b) When the disk is at its final speed, what is the tangential velocity of the bug? (c) One second after the bug...
  34. M

    Centripetal acceleration of rotating cylinders

    find ω given centripetal acceleration Homework Statement It has been suggested that rotating cylinders about 9.0 mi long and 6.4 mi in diameter be placed in space and used as colonies. What angular speed must such a cylinder have so that the centripetal acceleration at its surface equals the...
  35. S

    Centripetal Acceleration on an Inclined Plane

    During revision for an exam I have tomorrow I came across a question that left me confused, and I wasn't entirely satisfied with my teacher's explanation today. I'm worried something of the sort may come up in the exam and I won't be entirely certain how to deal with it. We have a plane...
  36. S

    Orbits of the planets and centripetal acceleration

    [b]1. The table below lists the average distance from each planet to the Sun and the time each planet takes to make a complete orbit around the Sun (“Orbital period”). The orbits of all of the planets are roughly circular. Your job is to determine a relationship between the radius r of a...
  37. D

    Centripetal acceleration on Earth

    Homework Statement An object orbits the Earth at a constant speed in a circle of radius 6.38 x 106 m, very close to but not touching the Earth's surface. What is its centripetal acceleration? Homework Equations a = v2/r = 4\pi2v/T2 v = 2\pir/T The Attempt at a Solution I plugged in...
  38. P

    Centripetal Acceleration at Equator

    Homework Statement An individual standing at the equator: a)What is this individuals centripetal acceleration caused by the Earth's rotation? b)How fast would the Earth need to spin in order for the centripetal acceleration to be equal to g? T=1 day radius of Earth = 6.4x10^6 m...
  39. W

    How Massive Must a Neutron Star Be to Keep Its Surface Intact While Rotating?

    certain neutron stars rotate at about 1.0 revolutions per second. If such a star has a raduis of 20km, what minimum mass must it have so that material on its surface doesn't fly off during the rapid rotation? ive tried working out the centripetal acceleration, being 7.89 X10^8 then subbed...
  40. R

    Centripetal acceleration of a satellite orbiting Earth

    Homework Statement A satellite is orbiting the Earth in a stable orbit of which the radius is twice that of the Earth. Find the ratio of the satellites cepripetal acceleration to g on the Earth's surface. Homework Equations centripetal acceleration = (v^2)/r or (4rpi^2)/T^2 The...
  41. G

    Angular, linear velocity & centripetal acceleration

    Homework Statement A washing machine's two spin cycles are 328 rev/min and 542 rev/min. The diameter of the drum is 0.43 m. What is the ratio of the centripetal accelerations for the fast and slow spin cycles? Homework Equations ac=v2/r linear velocity: v=rw (w is really omega) angular...
  42. A

    Centripetal Acceleration & Frictional Force

    Homework Statement A certain light truck can go around a flat curve having a radius of 150 m with a maximum speed of 32.0 m/s. With what maximum speed can it go around a curve having a radius of 75.0 m? Homework Equations Fc = m(v^2/r) Fc = net centripetal force m = mass v = tangenital speed r...
  43. O

    Calculating centripetal acceleration between moon and satelite

    Homework Statement http://www.screencast.com/users/trinhn812/folders/Jing/media/e79a7b88-f71e-4790-a35c-7bc0c3e03ec8 Answer key is marked Homework Equations F=gMm/r^2 =ma=mv^2/R The Attempt at a Solution So does gMm/r^2 also measure centripetal acceleration?
  44. F

    A question about centripetal acceleration

    http://img517.imageshack.us/img517/4817/aholelol.png http://img532.imageshack.us/img532/881/bridgelol.png There are 2 images. Let ac be the centripetal acceleration vector and v the speed vector. Now are my drawing right or have I gotten this whole thing wrong? My teacher said that the...
  45. H

    Calculating Centripetal Acceleration Angle for a Race Car on a Circular Track

    Homework Statement A race car starts from rest on a circular track. The car increases its speed at a constant rate at as it goes 2.25 times around the track. Find the angle that the total acceleration of the car makes with the radius connecting the center of the track and the car at the moment...
  46. H

    Centripetal acceleration v^2/r?

    can someone justify why centripetal acceleration = v^2/r? And I'm not asking about algebraic proof.
  47. D

    Centrifuge - find centripetal acceleration

    Homework Statement You are designing a centrifuge to spin at a rate of 15,300 rev/min. (a) Calculate the maximum centripetal acceleration that a test-tube sample held in the centrifuge arm 14.7 cm from the rotation axis must withstand. 377361.36 m/s2 (b) It takes 1 min, 16 s for the...
  48. M

    Centripetal acceleration at equator

    The centripetal acceleration of a person standing at the equator is about 0.03 m s–2. (Radius of the Earth = 6.4 × 106 m.) The size of the force R provides a measure of the apparent strength of the gravitational field. Show that the apparent field strength g at the equator differs from...
  49. M

    How Far Can a Spider Safely Cling to a Spinning Ceiling Fan Blade?

    A ceiling fan is turning at a rate of 100 revolutions per minute. A spider is clinging to a blade. If he experiences a centripetal acc greater than 0.3g, he wil lose his grip and be flung off. How far from the centre can he safely go? I used: T = 60/100 = 0.6 angular velocity = 2pi/T =...
  50. majormuss

    Forces- Centripetal acceleration

    Homework Statement What is the Shape of graph that represents Centripetal acceleration as a function of time? Homework Equations The Attempt at a Solution I know its a parabola, but am not sure how the curve is going to look.
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