Section 5.1 WorkChapter 5 Problems1, 2, 3 = straightforward, intermediate, challenging = full solution available in Student Solutions Manual/Study Guide = co ached solution with hints available at www.cp7e.com = biomedical applicationSection 5.1 Work 1. A weight lifter lifts a 350-N set of weights from ground level to a position over his head, a vertical distance of 2.00 m. How much work does the weight lifter do, assuming he moves the weights at constant speed? 2. If a man lifts a 20.0-kg bucket from a well and does 6.00 kJ of work, how deep is the well? Assume that the speed of the bucket remains constant as it is lifted. 3. A tugboat exerts a constant force of 5.00 × 103 N on a ship moving at constant speed through a harbor. How much work does the tugboat do on the ship if each moves a distance of 3.00 km? 4. A shopper in a supermarket pushes acart with a force of 35 N directed at an angle of 25° downward from the horizontal.Find the work done by the shopper as she moves down a 50-m length of aisle. 5. Starting from rest, a 5.00-kg block slides 2.50 m down a rough 30.0° incline. The coefficient of kinetic friction between the block and the incline is μk = 0.436. Determine (a) the work done by the force ofgravity, (b) the work done by the friction force between block and incline, and (c) the work done by the normal force. 6. A horizontal force of 150 N is used topush a 40.0-kg packing crate a distance of 6.00 m on a rough horizontal surface. If the crate moves at constant speed, find (a) the work done by the 150-N force and (b) the coefficient of kinetic friction between the crate and surface. 7. A sledge loaded with bricks has a total mass of 18.0 kg and is pulled at constant speed by a rope inclined at 20.0° above the horizontal. The sledge moves a distance of 20.0 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is 0.500. (a) What is the tension in the rope? (b) How much work is done by the rope on the sledge? (c) What is the mechanical energy lost due to friction? 8. A block of mass 2.50 kg is pushed 2.20 m along a frictionless horizontal table by a constant 16.0-N force directed 25.0° below the horizontal. Determine the work done by (a) the applied force, (b) the normalforce exerted by the table, (c) the force of gravity, and (d) the net force on the block. Section 5.2 Kinetic Energy and the Work–Energy Theorem 9. A mechanic pushes a 2.50 × 103-kg car from rest to a speed of v, doing 5 000 J ofwork in the process. During this time, the car moves 25.0 m. Neglecting friction between car and road, find (a) v and (b) the horizontal force exerted on the car. 10. A 7.00-kg bowling ball moves at 3.00 m/s. How fast must a 2.45-g Ping-Pong ball move so that the two balls have the same kinetic energy? 11. A person doing a chin-up weighs 700N, exclusive of the arms. During the first 25.0 cm of the lift, each arm exerts an upward force of 355 N on the torso. If the upward movement starts from rest, what is the person’s velocity at that point? 12. A crate of mass 10.0 kg is pulled up arough incline with an initial speed of 1.50 m/s. The pulling force is 100 N parallel to the incline, which makes an angle of 20.0° with the horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 5.00 m. (a) How much work is done by gravity? (b) How much mechanical energy is lost due to friction? (c) How muchwork is done by the 100-N force? (d) What is the change in kinetic energy of the crate? (e) What is the speed of the crate after beingpulled 5.00 m? 13. A 70-kg base runner begins his slide into second base when he is moving at a speed of 4.0 m/s. The coefficient of friction between his clothes and Earth is 0.70. He slides so that his speed is zero just as he reaches the base. (a) How much mechanical energy is lost due to friction acting on the runner? (b) How far does he slide? 14. An outfielder throws a 0.150-kg baseball at a speed of 40.0 m/s and an initial angle of 30.0°. What is the kinetic energy of the ball at the highest point of its motion? 15. A 2.0-g bullet leaves the barrel of a gun at a speed of 300 m/s. (a) Find its kinetic energy. (b) Find the average force exerted by the expanding gases on the bullet as it moves the length of the 50-cm-long barrel. 16. A 0.60-kg particle has a speed of 2.0 m/s at point A and a kinetic energy of 7.5 J at point B. What is (a) its kinetic energy at A? (b) its speed at point B? (c) the total workdone on the particle as it moves from A to B? 17. A 2 000-kg car moves down a level highway under the actions of two forces: a 1000-N forward force exerted on the drive wheels by the road and a 950-N resistive force. Use the work–energy theorem to find the speed of the car after it has moved a distance of 20 m, assuming that it starts from rest. 18. On a frozen pond, a 10-kg sled is given a kick that imparts to it an initial speed of v0 = 2.0 m/s. The coefficient of kinetic friction between sled and ice is μk = 0.10. Use the work–energy theorem to find the distance the sled moves before coming to rest.Section 5.3 Gravitational Potential Energy Section 5.4 Spring Potential Energy 19. Find the height from which you would have to drop a ball so that it would have a speed of 9.0 m/s just before it hits the ground. 20. A flea is able to jump about 0.5 m. It has been said that if a flea were as big as a human, it would be able to jump over a 100-story building! When an animal jumps, it converts work done in contracting muscles into gravitational potential energy (with some steps in between). The maximum force exerted by a muscle is proportional to its cross-sectional area, and the work done by the muscle is this force times the length of contraction. If we magnified a flea by a factor of 1 000, the cross section of its muscle would increase by 1 0002 and the length of contraction would increase by 1 000. How high would this “superflea” be able to jump? (Don’t forget that the mass of the “superflea” increases as well.) 21. An athlete on a trampoline leaps straight up into the air with an initial speed of 9.0 m/s. Find (a) the maximum height reached by the athlete relative to the trampoline and (b) the speed of the athlete when she is halfway up to her maximum height. 22. Truck suspensions …