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HOMEWORK 6.B - SP 24
4 thoughts on “HOMEWORK 6.B - SP 24”
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I've finished this homework, but just as a warning to others, remember to double check the vector directions with the right-hand rule and not mix up the direction of the tension vectors - I was getting the opposite of what I should have on my first few attempts.
for homework 6b i don't understand why the angle phi matters. if the moment about point O is the perpendicular force multiplied by distance from O then the value phi changes nothing. this is because the angle of the force relative to the bar is always theta and the distance is always OD. so why do they give the value 30 for phi, do you use it?
I used the cross product of the position vector OD and the tension DA to find the moment, and so to find the tension vector I used the tangent of theta to find the distance between O and A, then the sine and cosine of phi for the x and y components of the tension. However, if you found the moment by multiplying the distance by the magnitude of the tension by the sine of theta, I think you get the same answer.
To clarify, I think you can find the magnitude of the moment without using phi (by multiplying the distance by the tension by the sine of theta), but I think you would need to use phi to find the moment vector.