pg 68 Q1 Q.1: Determine the net force acting on each of the following objects. In each case assume that all forces acting on the object are given. K (a) At an instant when a soccer ball is slightly off the ground, a player kicks it, exerting a force of 28 N at 50.0 above the horizontal. The force of gravity acting on the ball is 3.2 N [down]. (b) Two children pull a sled across the ice. One child pulls with a force of 10 N [N 350 E], and the other pulls with a force of 28 N [N 540 W]. There is negligible friction acting on the sled. (c) In a circus act, a performer with a force of gravity of 4.2 x 102 N on her is lifted by two different ropes at the same time. One rope exerts a tension of 4.3 x 102 N [up and 35 left], and the other rope exerts a force of 3.2 x 102 N [up]. pg 73 Q2 2. Two students push horizontally on a large, 75 kg trunk. The trunk moves east with an acceleration of 3.0 m/s2. One student pushes with a force of 2.4 x 102 N [E 450 S]. The force of friction acting on the trunk is 1.8 x 102 N [W]. Determine the force that the other student applies to the trunk. p9 79 22 3. A 72 kg rock climber is attached to a rope that is allowing him to hang horizontally with his feet against the wall. The tension in the rope is 8.1 x 102 N, and the rope makes an angle of 30 with the horizontal. Determine the force exerted by the wall on the climber's feet. 29110 Q 2 4. You use a string to suspend a cork ball with a mass of 24.0 g from the ceiling of a moving speedboat. The ball and string hang at an angle of 32.50 from the vertical. (a) Calculate the magnitude of the speedboat's acceleration. Do you need to know the mass of the ball to make this calculation? Why or why not? (b) Determine the magnitude of the tension in the string. Do you need to know the mass of the ball to make this calculation? Why or why not? 29 123 Q1 5. A model airplane with a mass of 0.311 kg pulls out of a dive. The bottom of the dive is a circular arc with a radius of 24.6 m. At the bottom of the arc, the plane's speed is a constant 22.7 m/s. Determine the magnitude of the upward lift on the plane's wings at the bottom of the arc