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Physics .. 2 questions !

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3  Aug 31, 2014

#3
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Not necessarily, the question mentions that the weight is supported by the two wires which indicates it's at rest.

Sep 1, 2014

#1
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The first problem can be solved with trigonomy.

To sustain the weight each cord will need to deliver a power of 50N on the y-axis.

You can represent the forces in a triangle like this, in which |AC| is the power delivered by tension in the cord: |BC|=50 N so |AC|=|BC|/cos(50)=50/cos(50)=77.79. This means each cord delivers a power of 77.79N due to tension. Which would mean that the correct answer is D.

The second problem can be solved with the formula:

$${\frac{\left({Y}{\left({\mathtt{A}}\right)}{\mathtt{\,-\,}}{Y}{\left({\mathtt{B}}\right)}\right)}{\left({X}{\left({\mathtt{A}}\right)}{\mathtt{\,-\,}}{X}{\left({\mathtt{B}}\right)}\right)}} = {\mathtt{slope}}$$

We take the points A (-4,0) and B (0,-6) and insert them in the formula:

$${\frac{\left({\mathtt{0}}{\mathtt{\,\small\textbf+\,}}{\mathtt{6}}\right)}{\left({\mathtt{\,-\,}}{\mathtt{4}}{\mathtt{\,\small\textbf+\,}}{\mathtt{0}}\right)}} = {\mathtt{\,-\,}}{\frac{{\mathtt{3}}}{{\mathtt{2}}}} = -{\mathtt{1.5}}$$

Aug 31, 2014
#2
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for question 20 ...

I think that they should say in the question that the weight is in Equilibrium   right ~ !

Sep 1, 2014
#3
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