Angular acceleration Definition and 566 Threads

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. T

    Solving Angular Acceleration: Tips and Help for Inclined Planes and Formulas

    Homework Statement http://img166.imageshack.us/img166/6047/cilinderox6.jpg Homework Equations Tangent Acceleration, Linear Acceleration The Attempt at a Solution I tried to made a free body diagram but i got confused with the inclined plane I am stuck there. Also with the...
  2. X

    Angular Acceleration of a Model Rocket

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  3. D

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    Homework Statement wheel rotates w constant acceleration 3.65rad/s2 angular speed is 3.00 rad/s at t=0 a)what angle does wheel rotate between t=0 and t=3.67s? b)what is angular speed of wheel at 4.1s? Homework Equations wt+1/2alphat (3.00rad/s)(3.67t)+1/2(3.65rad/s2)(3.67)2=17.70rad...
  4. P

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    Homework Statement Given that a wheel with w(1) = -44i, is mounted on a turntable with w(2) = 35k, determine overall angular velocity and acceleration. Give both magnitude and direction. Homework Equations a = w(1) X w(2) ? The Attempt at a Solution I got the correct angular...
  5. A

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  6. C

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  7. L

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  8. L

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  9. S

    Angular Acceleration of a grinding wheel

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  10. I

    How to find angular acceleration

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  11. A

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  12. B

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  13. A

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  14. X

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  15. S

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  16. J

    Finding a max angular acceleration

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  17. I

    Calculating Torque & Angular Acceleration of a Current Loop

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  18. M

    Angular Acceleration of a hammer

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  19. C

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  20. G

    Why Didn't Taking the Second Derivative Solve the Angular Acceleration Problem?

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  21. O

    Angular Acceleration: Find Angle in 2 Seconds

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  22. M

    Angular Acceleration of a bicycle

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  23. B

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  24. G

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  25. M

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  26. R

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  27. H

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  28. L

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  29. A

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    A space station is constructed in the shape of a wheel 23 m in diameter, with essentially all of its 7.9×10^5 kg mass at the rim. Once the station is completed, it is set rotating at a rate that requires an object at the rim to have radial acceleration g, thereby simulating Earth's surface...
  30. I

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  31. E

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  32. L

    How to Determine Angular Deceleration and Initial Speed of a Coasting Saw Blade?

    A circular saw blade completes 1200 revolutions in 40s while coasting to a stop after being turned off. Assuming constant deceleration, what are (a) the angular deceleration and (b) the initial angular speed? Answer in RPM/S Method I used: Change in theta is 1200 Time: 40s final Vel.:0...
  33. L

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  34. T

    Angular Acceleration vs Tangential Acceleration

    Im a little fuzzy on the difference between the two. If you look at the attached picture, if that force stays with the object as it rotates, like a hand pushing in the same spot, would that force cause an angular acceleration?
  35. W

    How Does Accelerating a Car Affect Its Engine's Angular Metrics?

    As you press down on the accelerator of your car you see the tachometer climb steadily from 1200 rpm to 5500 rpm in 2.5 s. (a) What is the angular acceleration of the car? (b) What is the tangential acceleration of a point on the edge of the engine’s 3.8 cm diameter crankshaft...
  36. R

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  37. R

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  38. R

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  39. T

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  40. B

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  41. W

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  42. M

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  43. T

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  44. N

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  45. K

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  46. B

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  47. I

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  48. clope023

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  49. J

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  50. M

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