- #1
FrogPad
- 810
- 0
I think I am getting the wrong answer here, but I don't know why. Would someone please be so kind to go through this basic stuff.
Question: The force F exerts a 200 ft-lb counterclockwise moment about A and a 100 ft-lb clockwise moment about B. What are F and theta?Attempt:
[tex] M_A = 2 F \cos \theta + 9 F \sin \theta = 200 [/tex]
[tex] M_B = -7 F \cos \theta + F \sin \theta = -100 [/tex]
A little bit of algebra yields:
[tex] \frac{\sin \theta}{\cos \theta} = \frac{12}{-11} [/tex]
[tex] \tan \theta = \frac{12}{-11} = -47.49 (deg) [/tex]
Would someone please tell me what I am doing wrong. Thanks!
Question: The force F exerts a 200 ft-lb counterclockwise moment about A and a 100 ft-lb clockwise moment about B. What are F and theta?Attempt:
[tex] M_A = 2 F \cos \theta + 9 F \sin \theta = 200 [/tex]
[tex] M_B = -7 F \cos \theta + F \sin \theta = -100 [/tex]
A little bit of algebra yields:
[tex] \frac{\sin \theta}{\cos \theta} = \frac{12}{-11} [/tex]
[tex] \tan \theta = \frac{12}{-11} = -47.49 (deg) [/tex]
Would someone please tell me what I am doing wrong. Thanks!