Problem 1CQ: Is it possible to do work on an object that remains at rest? Problem 2CQ: A friend makes the statement, Only the total force acting on an object can do work. Is this... Problem 3CQ: A friend makes the statement, A force that is always perpendicular to the velocity of a particle... Problem 4CQ: The net work done on a certain object is zero What can you say about its speed? Problem 5CQ: Give an example of a frictional force doing positive work. Problem 6CQ: A ski boat moves with constant velocity Is the net force acting on the boat doing work? Explain Problem 7CQ: A package rests on the floor of an elevator that is rising with constant speed. The elevator exerts... Problem 8CQ: An object moves with constant velocity Is it safe to conclude that no force acts on the object? Why,... Problem 9CQ: Engine 1 does twice the work of engine 2. Is it correct to conclude that engine 1 produces twice as... Problem 10CQ: Engine 1 produces twice the power of engine 2. Is it correct to conclude that engine 1 does twice as... Problem 1PCE: A pendulum bob swings from point I to point II along the circular arc indicated in Figure 7. (a) Is... Problem 2PCE: A pendulum bob swings from point II to point III along the circular arc indicated in Figure 7-19.... Problem 3PCE: A farmhand pushes a 26-kg bale of hay 3.9 m across the floor of a barn. If she exerts a horizontal... Problem 4PCE: Children in a tree house lift a small dog in a basket 3.85 m up to their house. If it takes 201 J of... Problem 5PCE: Early one October, you go to a pumpkin patch to select your Halloween pumpkin. You lift the 3.2-kg... Problem 6PCE: The coefficient of kinetic friction between a suitcase and the floor is 0.272. If the suitcase has a... Problem 7PCE: BIO Peristaltic Work The human snail intestine moves food along its 6.9-m length by means of... Problem 8PCE: Predict/Calculate A tow rope, parallel to the water, pulls a water skier directly behind the boat... Problem 9PCE: A child pulls a friend in a little red wagon with constant speed. If the child pulls with a force of... Problem 10PCE: A 57-kg packing crate is pulled with constant speed across a rough floor with a rope that is at an... Problem 11PCE: Predict/Calculate To clean a floor, a janitor pushes on a mop handle with a force of 50.0 N. (a) If... Problem 12PCE: A small plane tows a glider at constant speed and altitude. If the plane does 2.00 105 J of work to... Problem 13PCE: As a snowboarder descends a mountain slope, gravity, the normal force, and friction combine to exert... Problem 14PCE: A young woman on a skateboard is pulled by a rope attached to a bicycle. The velocity of the... Problem 15PCE: To keep her dog from running away while she talks to a friend, Susan pulls gently on the dogs leash... Problem 16PCE: Water skiers often ride to one side of the center line of a boat as shown in Figure 7-20. In this... Problem 18PCE: A pitcher throws a ball at 90 mi/h and the catcher stops it in her glove. (a) Is the work done on... Problem 19PCE: How much work is needed for a 73 kg runner to accelerate from rest to 7.7 m/s? Problem 20PCE: Skylabs Reentry When Skylab reentered the Earths atmosphere on July 11,1979, it broke into a myriad... Problem 21PCE: Predict/Calculate A 9.50-g bullet has a speed of 1.30 km/s. (a) What is its kinetic energy in... Problem 22PCE: The energy required to increase the speed of a certain car from 18 m/s to 24 m/s is 190 kJ. (a) What... Problem 23PCE: Predict/Explain The work W0 accelerates a car front 0 to 50 km/h. (a) Is the work required to... Problem 24PCE: Car A has a mass m and a speed u, car B has a mass m/2 and a speed 3u, car C has a mass 3m and a... Problem 25PCE: Predict/Calculate A 0.14-kg pinecone falls 16 m to the ground, where it lands with a speed of 13... Problem 26PCE: In the previous problem (a) how much work was done on the pinecone by air resistance? (b) What was... Problem 27PCE: At t = 1.0s, a 0.55-kg object is tailing with a speed of 6.5 m/s. At t = 2.0s, it has a kinetic... Problem 28PCE: After hitting a long fly ball that goes over the right fielders head and lands in the outfield, the... Problem 29PCE: Predict/Calculate A 1100-kg car coasts on a horizontal road with a speed of 19 m/s. After crossing... Problem 30PCE: A 65-kg bicyclist rides his 8 8-kg bicycle with a speed of 14 m/s/ (a) How much work must be done by... Problem 32PCE: A block of mass m and speed U collides with a spring, compressing it a distance x What is the... Problem 33PCE: A spring with a force constant of 3.5 104 N/m is initially at its equilibrium length. (a) How much... Problem 34PCE: Initially sliding with a speed of 4.1 m/s, a 1.5-kg block collides with a spring and compresses it... Problem 35PCE: The force shown in Figure 7-21 moves an object from x = 0 to x = 0.75 m. (a) How much work is done... Problem 36PCE: An object is acted on by the force shown in Figure 7-22. What is the final position of the object if... Problem 37PCE: To compress spring 1 by 0 20 m takes 150 J of work. Stretching spring 2 by 0 30 m requires 210 J of... Problem 38PCE: Predict/Calculate It takes 180 J of work to compress a certain spring 0.15 m. (a) What is the force... Problem 39PCE: The force shown in Figure 7-22 acts on a 1.3-kg object whose initial speed is 0.35 m/s and initial... Problem 40PCE: A block is acted on by a force that varies as (2.0 104 N/m)x for 0 x 0.21 m, and then remains... Problem 42PCE: Section 7-4 Power 42 CE Fore F1 does 5 J of work in 10 seconds, force F2 does 3 J of work in 5... Problem 43PCE: BIO Climbing the Empire State Building A new record for running the stairs of the Empire State... Problem 44PCE: Calculate the power output of a 14-mg fly as it walks straight up a windowpane at 2.3 cm/s. Problem 45PCE: An ice cube is placed in a microwave oven. Suppose the oven delivers 105 W of power to the ice cube... Problem 46PCE: Your car produces about 34 kw of power to maintain a constant speed of 31 m/s on the highway. What... Problem 47PCE: You raise a bucket of water from the bottom of a deep well. If your power output is 108 W, and the... Problem 48PCE: BIO Salmon Migration As Chinook salmon swim upstream in the Yukon River to spawn, they must travel... Problem 49PCE: In order to keep a leaking ship from sinking, it is necessary to pump 12.0 lb of water each second... Problem 50PCE: Predict/Calculate A kayaker paddles with a power output of 35.0 W to maintain a steady speed of 2.24... Problem 51PCE: BIO Human-Powered Flight Human-powered aircraft require a pilot to pedal, as in a bicycle, and... Problem 52PCE: Predict/Calculate Beating to Windward A sailboat can be propelled into the wind by a maneuver called... Problem 53PCE: Predict/Calculate A grandfather clock is powered by the descent of a 4.35-kg weight. b If the weight... Problem 54PCE Problem 57GP: CE As the three small sailboats shown in Figure 7-24 drift next to a dock, because of wind and water... Problem 58GP: CE Predict/Explain A car is accelerated by a constant force, F. The distance required to accelerate... Problem 59GP: CE Car 1 has four limes the mass of car 2, but they both have the same kinetic energy. If the speed... Problem 60GP: BIO Muscle Cells Biological muscle cells can be thought of as nanomotors that use the chemical... Problem 61GP: A small motor runs a lift that raises a load of bricks weighing 836 N to a height of 10.7 m in 23.2... Problem 62GP: You push a 67-kg box across a door where the coefficient of kinetic friction is k = 0.55. The force... Problem 63GP: A 1300-kg elevator is lifted at a constant speed of 1.3 m/s through a height of 22 in. How much work... Problem 64GP: CE The work W0 is required to accelerate a car from rest to the speed U0. How much work is required... Problem 65GP: After a tornado a 0.55-g straw was found embedded 2.3 cm into the trunk of a tree. If the average... Problem 66GP: You throw a glove straight upward to celebrate a victory. Its initial kinetic energy is K and it... Problem 67GP: The water skier in Figure 7-20 is at an angle of 32.5 with respect to the center line of the boat,... Problem 68GP: Predict/Calculate A sled with a mass of 5.80 kg is pulled along the ground through a displacement... Problem 69GP: Predict/Calculate A 0.19-kg apple falls from a branch 3 5 m above the ground. (a) Does the power... Problem 70GP: A boy pulls a bag of baseball bats across a ball field toward the parking lot. The bag of bats has a... Problem 71GP: At the instant it leaves the players hand after a jump shot, a 0.62-kg basketball is traveling 8.4... Problem 72GP: The force shown in Figure 7-25 acts on an object that moves along the x axis. How much work is done... Problem 73GP: A Compound Bow A compound bow in archery allows the user to hold the bowstring at full draw with... Problem 74GP: A Compound Versus a Simple Bow The compound bow in the previous problem requires 152 J of work to... Problem 75GP: Calculate the power output of a 0.42-g spider as it walks up a windowpane at 2.3 cm/s. The spider... Problem 76GP: Cookie Power To make a batch of cookies, you mix half a bag of chocolate chips into a bowl of cookie... Problem 77GP: Predict/Calculate A pitcher accelerates a 0.14-kg hardball from rest to 42.5 m/s in 0.060 s. (a) How... Problem 78GP: BIO Brain Power The human brain consumes about 22 W of power under normal conditions, though more... Problem 79GP: Meteorite On October 9, 1992, a 27-pound meteorite struck a car in Peekskill, NY, creating a dent... Problem 80GP: BIO Powering a Pigeon A pigeon in flight experiences a force of air resistance given approximately... Problem 81GP: Springs in Series Two springs, with force constants k1 and k2 arc connected in series, as shown in... Problem 82GP: Springs in Parallel Two springs, with force constants k1 and k2, are connected in parallel, as shown... Problem 83GP: A block rests on a horizontal frictionless surface. A string is attached to the block, and is pulled... Problem 84PP: BIO Microraptor gui: The Biplane Dinosaur The evolution of flight is a subject of intense interest... Problem 85PP: BIO Microraptor gui: The Biplane Dinosaur The evolution of flight is a subject of intense interest... Problem 86PP: BIO Microraptor gui: The Biplane Dinosaur The evolution of flight is a subject of intense interest... Problem 87PP: BIO Microraptor gui: The Biplane Dinosaur The evolution of flight is a subject of intense interest... Problem 93PP: Referring to Figure 7-15 Suppose the block has a mass of 1.4 kg and an initial speed of 0.62 m/s.... Problem 94PP: Predict/Calculate Referring to Figure 7-15 In the situation shown in Figure 7-15 (d), a spring with... Problem 95PP: Predict/Calculate Referring 10 Example 7-15 Suppose the car has a mass of 1400 Kg and delivers 48 hp... format_list_bulleted