คำศัพท์คณิตศาสตร์
The moment of the wrench couple must equal the sum of the moments given forces about point P through which R passes. The moments about three forces are(MOR 40(60) 40rk N.mm(MOR 40080-yi 400100-ajN.mma nd the total moment is M(800 40lyi(-4000 40xj(-40x 2oy)k N mm he direction cosines of Mare cos 0, (800 cos 0, (-4000 40x)/M(-40x 20y)/M cos here M is the magnitude of M. Equating the direction eosines of R and M gives 800-40y-4000 40x 24 olution of the three equations gives