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. S

    Problem using centripital accel.... Can you check my work?

    Homework Statement A student ties a 500 g rock to a 1.0-m-long string and swings it around her head in a horizontal circle. At what angular velocity in rpm does the string tilt down at a 16 degree angle? Homework Equations F = (m*v^2)/r v = r*w The Attempt at a Solution [/B] First I solved...
  2. R

    Why Is the Centripetal Acceleration Positive in Uniform Circular Motion?

    Homework Statement A child swings a tennis ball attached to a .750 m-string in a horizontal circle above his head at a rate of 5.00 rev/s What is the centripetal acceleration of the tennis ball? Homework Equations angular speed \omega = 2pi/T speed = r\omega a_c = -v^2 /r a_c = -\omega ^2...
  3. B

    Tangential and centripetal acceleration in circular motion

    I'm trying to understand the geometrical meaning of acceleration in circular motion. When I consider a particle moving in a circular path, I can clearly see that the acceleration vector can be composed of a tangential and radial component. But since the change in velocity happens over a period...
  4. C

    Ball Doing a Loop Min Kin Energy: Find Angle θ

    Homework Statement A ball with radius ##r## is inside a hollow cylinder with radius ##r+R##. In the first part of the assignment, one has to calculate the minimum kinetic energy the ball has to have at the bottom in order to complete a full loop in the cylinder. It turns out to be...
  5. Comeback City

    B Centripetal Acceleration of Photons?

    This question came to mind from the thread... https://www.physicsforums.com/threads/can-a-photon-be-accelerated.901484/ Knowing... 1) Strong gravitational fields create strong curves in spacetime 2) Light traveling through strong gravitational fields get curved along the spacetime 3)...
  6. C

    Rubber Band Spinning in midair

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  7. M

    Definition of centripetal force

    Homework Statement Hi, If an object is undergoing uniform circular motion, then the net force is acting perpendicular to the instantaneous velocity, and this is called the centripetal force. However, if the object is moving in a circle but the magnitude of its instantaneous velocity is not...
  8. T

    Centripetal acceleration help?

    Homework Statement Hi, I was wondering what is the difference between the equations an=w^2 x R vs an=V^2 / R? I thought both of these equations were the same? What is the normal acceleration at C and D? Homework Equations an=w^2 x R vs an=V^2 / R? The Attempt at a Solution [/B] If I use...
  9. M

    Is Centripetal Acceleration Treated as a Scalar or Vector Quantity?

    Recently, I was looking into centripetal acceleration and there's something I don't understand. According to my book, during uniform circular motion, the acceleration is a= v^2/r where v is the speed at which the object is moving and r is the radius of the circle. However, this formula is...
  10. Andreas C

    Centripetal acceleration derivation

    Ok, so I'm a bit confused by the derivation of a=v^2/r in Feynman's "Six Not-So-Easy Pieces". In pages 17-18, it is stated that "The other component of acceleration, at right angles to the curve, is easy to calculate, using Figures 1-7 and 1-8. In the short time Δt let the change in angle...
  11. RoboNerd

    Implementing angular momentum approach in problem

    Homework Statement An object is in uniform circular horizontal motion at the end of a chord of length L. Its tangential speed is v. The chord is pulled into length 0.5L in such a way that the tension in the chord remains constant. As a result, the tangential speed: a) remains constant b)...
  12. RoboNerd

    Question on energy conservation with centripetal acceleratio

    Homework Statement The right answer is E, and I have no idea how to solve this problem. Please advise on how to proceed. Thanks in advance. Homework Equations conservation of mechanical energy?? The Attempt at a Solution Many attempts were done, but I am lacking on theory with this. How...
  13. RoboNerd

    Question about circular motion of planets

    Homework Statement Homework Equations I know that Fc = m * centripetal acceleration, where the Fc = the force of gravity The Attempt at a Solution [/B] I was able to use process of elimination to get B for 25 correctly, but I am not able to understand how it is the right answer. How can...
  14. S

    Centripetal Acceleration formula derivation

    Hello, This is a very basic question. I am sure I am doing something wrong in the derivation as shown in the picture. But I am not able to find out where I am doing it wrong. It would be very helpful if you can pls. let me know what I am doing wrong here. Thanks
  15. R

    Exploring Centripetal Acceleration on a Hypothetical Planet

    Homework Statement Imagine another planet with an acceleration of 10.00 m/s^2 at its equator when ignoring the rotation of the planet. The radius is 6.2 x10^6 m. An object dropped at the equator yields an acceleration of 9.70 m/s^2. Determine the length of 1 day on this planet. Homework...
  16. R

    Calculating Centripetal Acceleration at Earth's Equator

    Homework Statement the centripetal acceleration of an object at Earth's equator results from the daily rotation of Earth. Calculate the object's centripetal acceleration, given that the radius of Earth at the equator is 6.38*10^6m. Homework Equations a=v^2/r The Attempt at a Solution I really...
  17. RoboNerd

    Question on Orbits and Kepler/Uni. Grav. Laws

    Homework Statement The picture has the problem question. OK. When the moon is at point B, the distance from the moon to the center of the planet is most nearly: A) (1/25) * rA B) (1/5) * rA C) (1/ sqrt(5) ) * rA D) rA E) sqrt(5) * rA. Homework Equations Newton's law of gravitation...
  18. Elvis 123456789

    Directions of centripetal acceration and gravity on Earth?

    Im picturing a stationary object at the equator of the earth, going around in uniform circular motion due to the Earth's rotation. The centripetal acceleration would point directly inwards into the Earth at all points in the circular rotation, and gravity would also point in the same direction...
  19. T

    What is the (higher order) time derivative of centripetal acceleration?

    Just using basic dimensional analysis, it appears the time derivative of centripetal acceleration is ## \vec{r} \omega^3 ##, but this intuitive guess would also extend to higher order time derivatives, no? Implying: ## \frac {d^n \vec{r}}{dt^n} = \vec{r} \omega^n ## It seems to follow from the...
  20. BensonCa

    Centripetal acceleration formula

    Homework Statement In a certain carnival ride, visitors enter a circular room with radius r=9.1m. The room then begins spinning around its center, reaching an angular speed of 1.7rad/s. What centripetal acceleration do the riders experience? Homework Equations ac= v^2/r The Attempt at a...
  21. D

    How to calculate centripetal acceleration in non-circular systems?

    How can you calculate centripetal acceleration in a non circular system(I.E. if wanted to calculate the centripetal acceleration in an eclipse, or a parabola how could I do that?)
  22. vetgirl1990

    Finding angular acceleration of pulley attached to a mass

    Homework Statement A block of mass 2kg (mb) can slide down a frictionless 53 degree inclune, but it is connected to a pulley of mass 4kg (mp with a radius of 0.5m. The pulley may be treated as a disk. What is the angular acceleration of the pulley? Homework Equations a = rα The Attempt at a...
  23. T

    Rotating platform on top of another rotating platform

    Homework Statement Have platform A that is being spun by a centrifuge with a radius R1 and centripetal velocity of w1. On top of platform A is a Lazy Susan (Platform B) that spins about a radius R2 with a centripetal velocity of w2. There are accelerometers placed on the the purple platform...
  24. C

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    It can be found in any advanced calculus textbook the proof that, for a "well-behaved" space curve, the acceleration vector can be decomposed into components along the tangent and normal unit vectors. The acceleration vector is always orthogonal to the binormal vector. The decomposition is...
  25. W

    Possible to use centripetal acceleration for this problem?

    Homework Statement [/B] Everywhere I looked they solved this problem with energy conservation, but is it possible to solve it using centripetal acceleration? Homework Equations The Attempt at a Solution I tried putting (mv^2/r)*sin (theta) - F= ma which i solved for a. This gives me...
  26. A

    Finding Centripetal acceleration in a vertical system

    Homework Statement Tarzan plans to cross a gorge by swinging in an arc from a hanging vine. If his arms are capable of exerting 1350 N on the vine, what is his acceleration at the point where the vine makes an angle of 45 degrees from the vertical assuming maximum speed at this point. His mass...
  27. S

    Uniform Circular Motion and Centripetal acceleration

    Homework Statement For a scene in a movie, a stunt driver drives a 1.20✕ 103 kg pickup truck with a length of 4.65 m around a circular curve with a radius of curvature of 0.333 km (Fig. 7.29). The truck is to curve off the road, jump across a gully 10.0 m wide, and land on the other side 2.96 m...
  28. H

    What is the centripetal acceleration of the bob-sleigh?

    Homework Statement At the Olympic bob-sleigh competition, a new (I admit, fairly boring...) track has been built, as drawn in the figure. It is composed of straight lines with lengths as indicated in the figure and 90.0 degree turns, each with the same radius of curvature r1 = r2 = r3 = r4...
  29. T

    Centripetal acceleration in separating protein

    Homework Statement Two protein having same density 1.35 g /cm^3 but with different diameter 4nm and 5nm. They are mixed at the top of a centrifuge tube that is of length 1cm. What is the centripetal acceleration needed to separate them before they move to the end of the tube? Homework...
  30. UMath1

    Centripetal Force Washing Machine

    I know that the centripetal force is the resultant force which points to the center. So in the case of a washing machine, what force pushes the clothes and water to the outer edge? There is not centrifugal force, but then how come all the clothes appear to get pushed to the circumference of the...
  31. A

    Centripetal Acceleration Question

    Homework Statement A skateboarder has to do a loop the vertical loop of a roller coaster track. The radius of the loop is 6.53 m, what is the minimum velocity the skateboarder must have to not fall off when he is at the top of the loop. Homework Equations Equation for centripetal...
  32. faiziqb12

    Is Centripetal Acceleration Constant in Uniform Circular Motion?

    Homework Statement i was going through uniform circular but a confusion popped out of my head . as i have read before the Rutherford atomic model was only rejected due to the fact that electrons moving in circular orbits need to accelerate constantly to maintain a uniform speed but the...
  33. Z

    Centripetal acceleration turntable problem

    Homework Statement A small container of water is placed on a turntable inside a microwave oven, at a radius of 12.0 cm from the center. The turntable rotates steadily, turning one revolution in each 7.25 s. What angle does the water surface make with the horizontal? Homework Equations F = ma a...
  34. toforfiltum

    Confused abt derivation of centripetal acceleration

    A comparison of corresponding parts of these two similar isosceles triangles yields velocity triangle displacement triangle where |-vo| = |vf| = v In a small time interval Δt, the arc length s → c. Okay, so I got this from Physics LAB, and I don't understand the last statement that...
  35. andyrk

    Tangential and Centripetal Acceleration in Circular Motion

    Why is there no component of tangential acceleration in uniform circular motion? I think its because when we apply the WE Theorem (Work-Energy Theorem) as follows: Work Done = ΔKE => F.S = 1/2*m*(vf2 - vi2), =>(ma).s = 1/2*m*(vf2 - vi2) => (ma).s = 1/2*m*(0) (since the speed remains constant in...
  36. T

    Can someone explain to me what centripetal acceleration?

    Homework Statement I also need help on a problem. but FIRST, can someone explain to me how radial acceleration relates to gravity and how gravity can be split up into tangential and radial accelerations and how that can be compared to radial acceleration ? I know the basic stuff..like if a...
  37. Chaos_Theory

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  38. F

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  39. D

    Centripetal Acceleration Outwards

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  40. Prashant91

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    Homework Statement : A centrifuge starts from rest and speeds up at 3400rpm after 50 seconds. a sample is at a distance of 37.5mm from the centre 1) find the angular acceleration 2) calculate the centripetal acceleration [/B] Homework Equations : v2 / r v = rω a = rω2 a=Λω/Λt 3. The...
  41. avito009

    Is the force for centripetal acceleration inversely proportional to the radius?

    Since F=mv2/r. Does that mean the force required for centripetal acceleration is inversely proportional to the radius? If radius is more the lesser centripetal force is required, is this correct?
  42. A

    Problem with Centripetal velocity on a banked corner

    first of all thanks for reading and especially thank you to people who helped with my previous question here https://www.physicsforums.com/threads/does-the-coefficient-of-friction-change-with-the-angle.798572/#post-5019349 Unfortunately i am having more problems with this instructor insisting...
  43. J

    Circular Motion and centripetal acceleration

    Homework Statement Q.1. Explain the changes in the tension of a piece of string which is being swung vertically with a bucket of water at the end. What would the minimum centripetal acceleration need to be for water to not fall out?Homework Equations ac = v^2/r The Attempt at a Solution The...
  44. _N3WTON_

    Centripetal Acceleration of rocket car

    Homework Statement A rocket car is constrained to move on an elliptical track (semi-major axis a and semi-minor axis b ). The car is moving at a constant speed v_0 . Determine the acceleration of the car in \frac{m}{s^2} . a = 4 \hspace{2 mm} km , b = 2 \hspace{2 mm} km , and v_0 = 360...
  45. H

    Centripetal Acceleration for non uniform speed

    Homework Statement An airplane flies in a loop (a circular path in a vertical plane) of radius 120m . The pilot's head always points toward the center of the loop. The speed of the airplane is not constant; the airplane goes slowest at the top of the loop and fastest at the bottom. At the top...
  46. HTHLAndre

    Proving Centripetal Acceleration Physically?

    How Can I Prove this Physically Homework Statement [/B] So I need to do a project where I prove centripetal acceleration. All the cases I've seen of where it's proved is using formulas, though I need an actual project. By an actual project I mean something like...
  47. P

    Help with physics of flight paths?

    Hi all, If anything here is incorrect or confusing or seems trivially simple, I apologize: I'm not a physicist and created an account specifically to get help on this from some people who are! My question is this: Assume a plane has a constant airspeed and you wish to fly a circular pattern...
  48. L

    Centripetal acceleration of objects in orbit around the Earth

    Hi all. The answer to this might be trivial. If it is, sorry for posting. If you calculate the acceleration due to gravity of an orbiting satellite, it could be around 8.5-9.5m.s-2, depending. So, it's tangential velocity is such that as it falls towards earth, Earth curves away and the...
  49. S

    Centripetal Acceleration at top of Loop

    Homework Statement A roller coaster is on a track that forms a circular loop in the vertical plane. If the car is to just maintain contact at the top of the loop, what is the minimum value for its centripetal acceleration at this point? A) 2g downward B) g downward C) 2g upward D) g upward E)...
  50. S

    Determine the magnitude of its radial acceleration for ball

    < Mentor Note -- Thread moved from the General Physics forum to HH > A ball swings counterclockwise in a vertical circle at the end of a rope 1.50 m long. When the ball is 36.9 degrees past the lowest point on its way up, its total acceleration is (-22.5i + 20.2j) m/s^2. For that instant, (a)...
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