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Phy 121
Your 'cq_1_26.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** CQ_1_26.1_labelMessages.txt **
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A simple pendulum has length 2 meters. It is pulled back 10 cm from its equilibrium position and released. The tension in the string is 5 Newtons.
• Sketch the system with the pendulum mass at the origin and the x axis horizontal.
answer/question/discussion: ->->->->->->->->->->->-> :
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• Sketch a vector representing the direction of the pendulum string at this instant. As measured from a horizontal x axis, what is the direction of this vector? (Hint: The y component of this vector is practically the same as the length; you are given distance of the pullback in the x direction. So you know the x and y components of the vector.)
answer/question/discussion: ->->->->->->->->->->->-> :
The direction of the vector in relation to the positive x axis would be 93 degrees because the angle in relation to the negative x axis is 87 degrees. I found this by using the arc cos of (10/200) = 87. Given that the x axis is 180 degrees, the direction in relation to the positive x axis will be 93 because 180-87=93.
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• What is the direction of the tension force exerted on the mass?
answer/question/discussion: ->->->->->->->->->->->-> :
The direction of the force exerted will be 93 degrees because it is in the same direction as the pendulum.
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• What therefore are the horizontal and vertical components of the tension?
answer/question/discussion: ->->->->->->->->->->->-> :
The horizontal component of tension is .26 N because sin(3)*5 = .26N. The vertical component of tension is 4.99N because cos(3)*5 = 4.99N.
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• What therefore is the weight of the pendulum, and what it its mass?
answer/question/discussion: ->->->->->->->->->->->-> :
Therefore the weight of the pendulum is 4.99N and the mass of the pendulum is .51kg because 4.99N/9.8m/s = .51kg.
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• What is its acceleration at this instant?
answer/question/discussion: ->->->->->->->->->->->-> :
The acceleration at this instant would be 9.8m/s^2 because it is equal to that of gravity.
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This would be the acceleration if the string wasn't there.
The string tension effectively cancels the downward force of the weight, leaving only the horizontal component of the tension to accelerate the mass.
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Good, except for the last result.
&#Please see my notes and submit a copy of this document with revisions, comments and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).
Be sure to include the entire document, including my notes. &#
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