4. Express the position vector r in Cartesian vector form; then determine its magnitude and coordinate direction angles. x 8 ft B 2 ft r 30 20 5 ft A 1. A frame ABC is supported in part by cable DBE that passes through a frictionless ring at B. Knowing that the tension in the cable is 385 N, determine the components of force exerted by the cable on the supports at D and E. Express forces in Cartesian vector form. (Note orientation of axes). 510 mm 280 mm D 210 mm E 480 mm B 600 mm 400 mm