7.15 Knowing that the radius of each pulley is 120 mm and neglecting fric- tion, determine the internal forces at (a) point C, (b) point J that is 100 mm to the left of C. 200 mm 200 mm 300 mm 300 mm E A D B 600 N Fig. P7.15 and P7.16 716 Knowing that the radius of each pulley is 100 mm and neglecting fric- tion, determine the internal forces at (a) point C, (b) point J that is 100 mm to the left of C