Newton’s 3 rd Law of Motion

1. Newton’s 3rd Law of Motion Action - Reaction

7. Application of Newton’s Laws Object at equilibrium

8. Exercise # 2 Find the tension in each cable supporting the 600 N cat burglar. Suppose the horizontal cable were reattached higher up on the wall. Would the tension in the other cable increase, decrease or stay the same? Why? T 1 T2 T 1 = 997 N T2 = 796 N

9. Exercise # 3 The leg and the cast weigh 220 N (w1). Determine the weight w2 and the angle α needed that no force is exerted on the hip joint by the leg plus the cast. α = 60.550 T2 = 171.4 N

10. Exercise # 4: Incline planes A sled is tied to a tree on a frictionless, snow-covered hill. If the sled weighs 77 N, find the magnitude of the tension T exerted by the rope on the sled and the normal force n exerted by the hill on the sled. Exercise # 5: Suppose a child of weight w climbs onto the sled. If the tension force is measured to be 60 N, find the weight of the child and the magnitude of the force normal acting on the sled. W= 43N; Fn = 104N

11. Exercise # 6: All systems are at equilibrium. What do the spring scales read? Ignore the masses of the pulleys and strings.

12. 50N

13. 50N

16. Exercise # 7: Two blocks of masses m and 2m are held in equilibrium on a frictionless incline. In terms of m and θ, find The magnitude of tension T1 in the upper cord The magnitude of tension T2 in the lower cord connecting the two blocks