Phy 201
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.
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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: ->->->->->->->->->->->-> :
• 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 would be downward? I am confused by this do you mean the angle? In that case it would be tan^-1(10/2) which gives 78.7 degrees right of the vertical, which will then give theta of 11.3 degrees north of the horizontal
That would be 78.7 degrees as measured from the positive x axis, i.e., from horizontal.
• What is the direction of the tension force exerted on the mass?
answer/question/discussion: ->->->->->->->->->->->-> : Wouldn’t this be the same as the direction of the vector? 11.3 degrees north of the horizontal?
• What therefore are the horizontal and vertical components of the tension?
answer/question/discussion: ->->->->->->->->->->->-> :
y= 5Nsin(11.3)=.98N
X= 5Ncos(11.3)= 4.9N
• What therefore is the weight of the pendulum, and what it its mass?
answer/question/discussion: ->->->->->->->->->->->-> : w= tension or 5N.
5N=9.8(mass) mass=.51kg
• What is its acceleration at this instant?
answer/question/discussion: ->->->->->->->->->->->-> : f=m(a)
5N=.51kga
A=9.8m/s/s
?????????These answers are off, I am missing a step somewhere. I think it is where I converted tension to weight, if they were the same there would be no movement right? I am not sure how to do this step. ???????
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20mins
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You've got most of it, you just aren't quite interpreting it correctly. You're mostly just missing the interpretation of the angle you found. Check my note, then see the link:
&#Please compare your solutions with the expanded discussion at the link
Solution
Self-critique your solutions, if this is necessary, according to the usual criteria. Insert any revisions, questions, etc. into a copy of this posted document. Mark any insertions with &&&& so they can be easily identified. &#