19querry

course phy201

assignment #019019. `query 19

Physics I

04-20-2008

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17:34:14

Query class notes #20

Explain how we calculate the components of a vector given its magnitude and its angle with the positive x axis.

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RESPONSE -->

multiply the cosine of the angle by the magnitude of the component

confidence assessment: 1

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17:34:28

** STUDENT RESPONSE:

x component of the vector = magnitude * cos of the angle

y component of the vector = magnitude * sin of the angle

To get the magnitude and angle from components:

angle = arctan( y component / x component ); if the x component is less than 0 than we add 180 deg to the solution

To get the magnitude we take the `sqrt of ( x component^2 + y component^2) **

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RESPONSE -->

self critique assessment: 1

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Your response did not agree with the given solution in all details, and you should therefore have addressed the discrepancy with a full self-critique, detailing the discrepancy and demonstrating exactly what you do and do not understand about the given solution, and if necessary asking specific questions (to which I will respond).

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17:35:59

** If one person pulls with the given force F in the given direction the effect is identical to what would happen if two people pulled, one in the x direction with force Fx and the other in the y direction with force Fy. **

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RESPONSE -->

A person pulls with the given force in the given direction the effect is identical to what would happen if two people pulled, one in the x direction with force Fx and the other in the y direction with force Fy.

self critique assessment: 2

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17:43:09

** Using initial conditions and the equations of motion we can determine the x and y velocities vx and vy at a given point, using the usual procedures for projectiles.

The magnitude of the velocity is sqrt(vx^2 + vy^2) and the angle with the pos x axis is arctan(vy / vx), plus 180 deg if x is negative. **

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RESPONSE -->

By taking the square root of the velocity ""x"" squared plus the velocity ""y"" squared and the angle of position ""x"" is artan(vy/vx); you would add 180 degree if the ""x"" is negative.

self critique assessment: 2

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17:44:50

** Initial vel in the x direction is v cos(theta), where v and theta are the magnitude and the angle with respect to the positive x axis.

Initial vel in the y direction is v sin(theta). **

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RESPONSE -->

Initial vel in the x direction is v cos(theta), where v and theta are the magnitude and the angle with respect to the positive x axis and in the y-axis the velocity is v sin(theta)

self critique assessment: 1

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Your work looks good. Let me know if you have any questions. &#