cq_1_261

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 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: ->->->->->->->->->->->-> :

#$&* Using arctan(2cm / 10cm), I get the direction of this vector to be 11.31 degrees.

that would be 2 meters / 10 cm, not 2 cm / 10 cm

• What is the direction of the tension force exerted on the mass?

answer/question/discussion: ->->->->->->->->->->->-> :

#$&* I think that the tension force exerted on the mass is directed towards the center.

• What therefore are the horizontal and vertical components of the tension?

answer/question/discussion: ->->->->->->->->->->->-> :

#$&* I think the horizontal component would be 5 * cos(101.3) = -0.98 and the vertical component would be 5 * sin(101.3) = 4.9

• What therefore is the weight of the pendulum, and what it its mass?

answer/question/discussion: ->->->->->->->->->->->-> :

#$&* Weight is a component of gravity, which works in a straight downward direction. I think what I need to do is set the weight equal to the y component, since it too works in a straight downwards direction. So weight = 4.9 N, and the mass therefore is 4.9 / 9.8m/s^2 = 0.5 kg.

• What is its acceleration at this instant?

answer/question/discussion: ->->->->->->->->->->->-> :

#$&* The acceleration should be of that due to gravity, which would be 9.8m/s^2.

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over 20 minutes....

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See my note, think through your corrections, then check the link below. Submit a revision if you don't get everything; otherwise I think you'll be OK here. But be sure. This is important.

&#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. &#