# Rotation

## Sample Problem

Sample Problem While you are operating a Rotor (the rotating cylindrical ride discussed , you spot a passenger in acute distress and decrease. (a) What is the constant angular acceleration during this decrease in angular speed? SOLUTION: Assume that the rotation is in the counterclockwise direction, and let the acceleration begin at time I = 0, at angular position 60, …

## Sample Problem

Sample Problem A grindstone  rotates at constant angular acceleration . At time I = 0, it has an angular velocity  a reference line on it is horizontal, at the angular position. (a) At what time after t = 0 is the reference line at the angular position 8 = 5.0 rev? SOLUTION: The Key Idea here is that …

## Rotation with Constant Angular Acceleration

Rotation with Constant Angular Acceleration In pure translation, motion with a constant linear acceleration (for example, that of a falling body) is an important special case.We displayed a series of equations that hold for such motion. In pure rotation, the case of constant angular acceleration is also important. and a parallel set of equations holds for this case also. …

## Are Angular Quantltles Vectors

Are Angular Quantltles  Vector We can describe the position, velocity, and acceleration of a single particle by means of vectors. If the particle is confined to a straight line, however, we do not really need vector notation. Such a particle has only two directions available to it, and we can indicate these directions with plus and minus signs. It is …

## Sample Problem

Sample Problem The disk in  is rotating about its  axis like a merry go  round. The angular position of a  reference line on the disk. (a) Graph the angular position of the disk versus time from t = – 3.0 s to t = 6.0 s. Sketch the disk and its angular position. SOLUTION: The Key …

## Angular Acceleration

Angular Acceleration If the angular velocity of a rotating body is not constant, then the body has an angular acceleration. Let  be its angular velocities at times  arid respectively. The average angular acceleration. Hold not only for the rotating rigid body as a whole but also for every particle of that body. The unit of angular acceleration is …

## Angular Velocity

Angular Velocity Suppose  that our rotating body is at angular position 81 at time t and at angular position  at time .We define the average angular velocity of the body in the time interval. If a particle moves in translation along an x axis, its linear velocity v is either positive or negative, depending on whether the particle …

## Angular Displacement

Angular Displacement If the body of rotates about the rotation axis as in, changing the angular position of the reference line from 81 to 82; the body undergoes an angular displacement. If a body is in transnational motion along an x axis. its displacements either positive or negative, depending on whether the body is moving in the positive …

## Angular Position

Angular Position Shows a reference line, fixed in the body, perpendicular to the rotation axis, and rotating with the body. The angular position of this line is the angle of the line relative to a fixed direction, which we take as the zero angular position.The angular position 9 is measured relative to the positive direction of the , …

## The Rotational Variables

The Rotational Variables We wish to examine the rotation of a rigid body about a fixed axis. A rigid body is a body that can rotate with  its parts locked together and without any change in its shape. A fixed axis means that the rotation occurs about an axis that does not . Thus, we shall not examine …