2. Study the traction system shown in Figure 11. The tension in the vertical cord above the mass is 22 N. A student claims that the tension in the vertical cord above the leg must be more than 22 N. Discuss the validity of this statement. W/U TA C fixed pulleys 570 22 N Figure 117. At the beach, three children pull on a floating toy. Child 1 pulls with a force of 15 N [N 24" E], child 2 pulls south, and child 3 pulls west. The net force on the toy is zero. Assume that there are no other significant forces acting on the toy. TA (a) Calculate the magnitude of the forces exerted by child 2 and child 3 on the toy. (b) Child 2 lets go, and the other children maintain the same force. Calculate the net force on the toy. (c) What force must child 3 exert on the toy to cancel the force of child 1 on her own?2. Two tractors pull a large rock east through a construction site with a net force of zero on the rock. Tractor 1 exerts a force of 1.2 x 10" N [E 12" N] on the rock, and tractor 2 exerts a force of 1.2 x 10' N [E 12' S]. A TM (a) Calculate the force of friction acting on the rock. [ans: 2.3 x 10* N [W]] (b) Discuss two ways someone could spot that the force of friction on the rock must be to the west before solving the problem. 3. Figure 10 shows three masses connected by wires and hung vertically. Draw an FBD for each mass, and determine the tensions in the three wires. Du T A [ans: top wire: 3.4 x 10' N; middle wire: 2.0 x 10'N; bottom wire: 1.3 x 10' N] 15.0 kg 7.0 kg 13.0 kg Figure 10