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**Lewis is a trapeze artist. He is hanging upside down on a swing bar; he is holding on to the swing bar with his knees. Lewis is holding his partner Amanda below him, who weighs 475 Newtons. Assume that Amanda moves on a circle that has a radius of 6.50 meters. At a swinging speed of 4.00 m/s, what force must Lewis apply to his partner Amanda when she is in the straight down position?**

**Relevant equations**

a

_{c}= v

^{2}/r

F

_{c}= (mv

^{2})/r

**The attempt at a solution**

Lewis has to provide the force that holds up Amanda's weight of 475 Newtons

**AND**also the centripetal force F

_{c}that accelerates Amanda through the circle.

The total force that Lewis has to provide is: F

_{total}= Weight

_{amanda}+ F

_{c}

**What I did to find F**

_{c}was to plug and chug:F

_{c}= mv

^{2}/r

F

_{c}= [48.46938776 kg * 4

^{2}m/s]/6.5

F

_{c}= 119.3092622

Then I used this value to plug into F

_{total}= Weight

_{amanda}+ F

_{c}

F

_{total}= 475 + 119.3092622 = 594.3092622 N

**HOWEVER**, on some discussions on this problem, they are saying that the circle is horizontal when Amanda is at the straight down position, and thus, the Fc is horizontal which requires that we use the horizontal component????? ....Firstly, I do not know what they are implying here...Secondly, there are others who solved the problem as I did. Can somebody please tell me which is correct? Here is the discussion on a similar problem but with different values: http://answers.yahoo.com/question/index?qid=20081018232148AABuLGD

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