What is Angular acceleration: Definition and 567 Discussions

In physics, angular acceleration refers to the time rate of change of angular velocity. As there are two types of angular velocity, namely spin angular velocity and orbital angular velocity, there are naturally also two types of angular acceleration, called spin angular acceleration and orbital angular acceleration respectively. Spin angular acceleration refers to the angular acceleration of a rigid body about its centre of rotation, and orbital angular acceleration refers to the angular acceleration of a point particle about a fixed origin.
Angular acceleration is measured in units of angle per unit time squared (which in SI units is radians per second squared), and is usually represented by the symbol alpha (α). In two dimensions, angular acceleration is a pseudoscalar whose sign is taken to be positive if the angular speed increases counterclockwise or decreases clockwise, and is taken to be negative if the angular speed increases clockwise or decreases counterclockwise. In three dimensions, angular acceleration is a pseudovector.For rigid bodies, angular acceleration must be caused by a net external torque. However, this is not so for non-rigid bodies: For example, a figure skater can speed up her rotation (thereby obtaining an angular acceleration) simply by contracting her arms and legs inwards, which involves no external torque.

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  1. S

    Angular Acceleration vector help

    Im a fairly new to physics and I have a homework question off mastering physics which is , A wheel is spinning at 43rpm with its axis vertical. After 15 sec , it's spinning at 61rpm with its axis horizontal. Find (a) the magnitude of its average angular acceleration and (b) the angle the average...
  2. N

    Find the Angular Acceleration with and Without the disk inertia

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  3. S

    Torque on a wheel and angular acceleration.

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  4. F

    Torque and angular acceleration of two discs

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  5. A

    Angular Acceleration problem.

    A wheel is spinning at 44 with its axis vertical. After 15 , it's spinning at 60 with its axis horizontal. Find (a) the magnitude of its average angular acceleration and (b) the angle the average angular acceleration vector makes with the horizontal. Just trying to work out what I'm doing wrong...
  6. N

    Calculate the Tension and Angular Acceleration in Log After Release

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  7. Sneakatone

    How to find angular acceleration

    a)t=0 t=7 190/60*2pi=19.8 2950/60*2pi=308 308/7=41 I don't know what to do with acceleration with t=0. b)for tangental I used the equation alpha*R for centripetal I used...
  8. Sneakatone

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  9. F

    Angular acceleration caused by mass over a pulley

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  10. R

    Rate of change of angular acceleration?

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  11. R

    Angular acceleration of a beam?

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  12. P

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  13. V

    Using gradient values of a graph to determine angular acceleration

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  14. P

    Constant angular acceleration problem

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  15. L

    Angular acceleration, density question

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  16. N

    Calculating Angular Acceleration of a Pulsar

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  17. E

    How to determine the angular acceleration using the right hand rule?

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  18. C

    Angular Acceleration of toy train

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  19. L

    Angular acceleration and displacement problem

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  20. L

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  21. Saitama

    Angular acceleration of the bar

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  22. P

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  23. P

    Tangential acceleration given radius and angular acceleration

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  24. F

    Angular acceleration in terms of angular velocity

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  25. C

    What creates the angular acceleration in a pulley?

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  26. L

    Angular Velocity and Angular Acceleration help

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  27. A

    Angular acceleration of a bucket attatched to a solid cylinder

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  28. S

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  29. P

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  30. R

    Angular Acceleration of Bicycle Wheels

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  31. F

    Help needed - Spinning wheel, torque, angular acceleration.

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  32. Jalo

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  33. S

    Calculating the Average Angular Acceleration of a CD

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  34. binbagsss

    Angular acceleration direction, rotating rigid bodies

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  35. F

    Spiral motion & angular acceleration (Question)

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  36. S

    Simple question on acceleration and angular acceleration

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  37. M

    Angular acceleration of a wheel formula

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  38. M

    Angular Acceleration Using Work and Energy Principals

    Homework Statement The chain of a workshop crane is 50 m long and has a mass of 3 kg/m. It is partially wound on a drum and the effective radius from the axis of the drum to the chain centre line is 0.2 m. The drum itself, including shaft and gear wheel has a mass of 100 kg and has a radius of...
  39. E

    Solving the Slender Ladder Problem: Angular Acceleration

    The slender ladder has a mass of 10 kg. It is released from rest in the position shown. Friction at the two contact surfaces are negligible. Determine the angular acceleration of the ladder. I summed forces in the x,y direction, summed moments about the ladder's center of mass, wrote a...
  40. J

    Compact disk angular acceleration

    Homework Statement A compact disc speeds from rest to 5200 rpms in 620 rad. Diameter is 5.0cm -how many revolutions did it make in this time -what is the angular acceleration in rad/s^2 -how long does ti take to reach this speed Homework Equations The Attempt at a Solution i was able to find...
  41. J

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    For a conical pendulum, there is an instantaneous centripetal acceleration. Does this mean there is an instantaneous angular acceleration of the pendulum towards the center?
  42. S

    Angular acceleration and Torque when rod reaches vertical position?

    Angular acceleration and Torque when rod reaches vertical position?? A rod (mass 1.30 kg, length .670 m) attached to a frictionless axis is released from rest in the horizontal position. What is the magnitude of the torque and angular acceleration when the rod has reached the vertical...
  43. W

    Angular Acceleration of a Pulley Supporting Two Hanging Masses

    Homework Statement Hi all! I'm working on a dynamics homework and have hit a wall here: "If the frictional moment at the pivot O is 2 N m, determine the angular acceleration of the grooved drum, which has a mass of 8 kg and a radius of gyration k = 225 mm. Ans: α = 0.622 rad/s^2 "...
  44. J

    Angular acceleration and angular velocity

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  45. J

    What is the difference between centripetal and angular acceleration?

    So as the title says, what is the difference between centripetal and angular acceleration? I already know that there is a difference in the equations for each of the components but can someone please explain it conceptually? Please use some examples in your explanation.
  46. P

    Force Required by Rockets and Angular Acceleration

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  47. S

    Angular acceleration problem / 99% sure I'm doing right but getting wrong answer

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  48. J

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  49. E

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  50. K

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