(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

please replace the force-couple system of the previous problem with a wrench. Please state the pitch of the wrench and the coordinates of the point at which the wrench axis intercepts the xy plane

2. Relevant equations

3. The attempt at a solution

ok there are 3 forces going in different directions at different points. the force-couple system they are referring too consists of the moment about point D (MD) and the resultant force (R) if I understand correctly.

MD = <2376.1, 950, -710>

R = <238.1, -46.9, 237.7>

note: 1 force created no moment because it was alligned with point D

pitch (p) = (R MD)/(magnitude of R^2) = 3.054

that much seems easy, im confident that i did that much correctly. I was trying what the book told me to do for the rest and I keep getting answers with infinity and unmatching answers. they said M1 = pR. so I did pR to get M1.

then they said: M1 + rXR = MD

so i need to figure out vector r. so i set rXR = MD - M1.

if i set r = <x,y,z> and plug that in then i get answers with infinity (for x,y, and z)

they ask for the xy axis so on my next attempt i set z = 0 and plugged in r = <x,y,0> then i got answers that didnt match...

any idea what I am doing wrong?

p.s.

i also tried just doing rXR = MD. i had the same results

OK i just relooked the part where i put in r = <x,y,0>

i came up with value for x and y but in the 3rd equation it doesnt add up to 0 like it should. it is off by .0722

is this a problem? or is it only a matter of signifigant figures? because if its just SF then i think i actually did the problem correctly. just let me know if you see anything wrong with the concept of what i explained

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Pitch and wrench

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**