Show all work and circle your final answer. 1. A helicopter of mass 2.3x105 kg accelerates straight upward by pushing downward on the air with its propeller. At a certain moment, it accelerates upward at 1.2 m/s. (a) Draw a free-body diagram for the helicopter. (b) What is the weight of the helicopter? (c) What is the magnitude of the force exerted by the helicopter on the air? (d) What is the magnitude of the force exerted by the air on the helicopter? 2. On a snowy day, a child sleds down a frictionless slope with a steady 19" incline. The combined mass of the child and sled is 47 kg- (a) Draw a free-body diagram for the child. (You may treat the child and sled as one object.) (b) What is the normal force exerted by the slope on the child? (c) What is the acceleration of the child along the slope? (d) The child's parent, who has a mass of 81 kg, joins the child on the sled for the next trip. What is their acceleration when they ride together? 3. A camper attaches the ends of a hammock to two trees 5.1 m apart using some strong rope of negligible mass. The camper, who is 77 kg, gets in the hammock, which hangs stationary halfway between the two trees but 1.0 meter below the two points where the ropes are attached to the trocs. - -| 1.0 my Camper 5.1 m (a) Draw a free-body diagram for the camper in the hammock. (b) Calculate the tension in each of the ropes attaching the hammock to the trees. Hint: find the angle each rope makes with the horizontal first. (c) Suppose the ropes anchoring the hammock can exert a maximum tension of 2.1 x 10* N before snapping. How massive would the camper have to be to break the hammock? 4. A train consists of three cars in a row. The first, the engine, has a mass of 7.40 x 104 kg. The second, the freight car, has a mass of 5.60 x 10* kg. The third, the caboose, has a mass of 4.80 x 10* kg. Each car is connected to the next by a chain. The force of the engine pulls the train forward at a rate of 0.210 m/s'. Assume the track is frictionless, level, and perfectly straight. (a) Draw a free-body diagram for the engine. (b) Draw a free-body diagram for the freight car. (c) Draw a free-body diagram for the caboose. (d) What is the tension in the chain connecting the engine and the freight car? (c) What is the tension in the chain connecting the freight car and the caboose