f5 phy(急) 40點!!!!

Tightrope walking is a form of acrobatic performance. When performing, the acrobat usually holds a pole horizontally in his hands.

圖片參考：http://img689.imageshack.us/img689/3430/23706571.jpg

The figures above represents two tightrope walking acrobats, one without a pole and the other with a pole in his hands. Two weights, each weighting
50N with negligible volumes, are attched to the two ends of the pole, and the mass of the pole itself is negligible. For both acrobats, the centre of gravity is 0.5m above the rope, the weight is 550N, and both acrobats experience a tilting of 5度 as they are moving on the rope. The acrobat with a pole does not adjust his arms, so the pole makes an angle of 5度 with the horizontal after tilting.

a) For acrobat A, what is the net moment about the rope when he makes an angle of 5度 with the vertical? (呢題我已搵到答案 net moment=24Nm )

b) What is the distance between the rope and the end of the pole?
(呢題我已搵到答案 distance=1.58m )

c) Hence, find the net moment about the rope when acrobat B makes an angle of 5度 with the vertical.