query 29

#$&*

course phy 201

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If your solution to stated problem does not match the given solution, you should self-critique per instructions athttp://vhcc2.vhcc.edu/dsmith/geninfo/labrynth_created_fall_05/levl1_22/levl2_81/file3_259.htm.

Your solution, attempt at solution. If you are unable to attempt a solution, give a phrase-by-phrase interpretation of the problem along with a statement of what you do or do not understand about it. This response should be given, based on the work you did in completing the assignment, before you look at the given solution.

029. `query 29

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Question: `qQuery class notes #28. Explain how we can calculate the average angular velocity and the angular acceleration of an object which rotates from rest through a given angle in a given time interval, assuming constant angular acceleration.

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Your solution:

distance /time

multiply by the angle

confidence rating #$&*:

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Given Solution:

`a**This situation is strictly analogous to the one you encountered early in the course. As before acceleration is change in velocity / change in clock time. However now it's angular acceleration.

We have

angular acceleration = change in angular velocity / change in clock time.

The average angular velocity is change in angular position / change in clock time.

This question assumes you know the angle through which the object rotates, which is its change in angular position, as well as the change in clock time.

So you can calculate the average angular velocity.

If angular accel is uniform and initial angular velocity is zero then the final angular velocity is double the average angular velocity. In this case the change in angular velocity is equal to the final angular velocity, which is double the average angular velocity.

From this information you can calculate angular acceleration. **

Principles of Physics and General College Physics Problem 7.46: Center of mass of system 1.00 kg at .50 m to left of 1.50 kg, which is in turn .25 m to left of 1.10 kg.

Using the position of the 1.00 kg mass as the x = 0 position, the other two objects are respectively at x = .50 m and x = .75 m.

The total moment of the three masses about the x = 0 position is 1.00 kg * (0 m) + 1.50 kg * (.50 m) + 1.10 kg * (.75 m) = 1.58 kg m.

The total mass is 1.00 kg + 1.50 kg + 1.10 kg = 3.60 kg, so the center of mass is at position

x_cm = 1.58 kg m / (3.60 kg) = .44 meters,

placing it a bit to the left of the 1.50 kg mass.

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Self-critique (if necessary):

angular acceleration = change in angular velocity / change in clock time.

The average angular velocity is change in angular position / change in clock time.

whoops messed up

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Self-critique Rating: