Problem 1RCQ: State the law of inertia. Problem 2RCQ: Is inertia a property of matter or a force of some kind? Problem 3RCQ: What concept was missing from people's minds in the 16th century when they couldn't believe Earth... Problem 4RCQ: When a bird lets go of a branch and drops to the ground below, why doesn't the moving Earth sweep... Problem 5RCQ: What kind of path would the planets follow if suddenly their attraction to the Sun no longer... Problem 6RCQ: State Newton's second law. Problem 7RCQ: Is acceleration directly or inversely proportional to force? Give an example. Problem 8RCQ: Is acceleration directly or inversely proportional to mass? Give an example. Problem 9RCQ: If the mass of a sliding block is tripled at the same time that the net force on it is tripled, how... Problem 10RCQ: What is the net force that acts on a 10-N freely falling object? Problem 11RCQ: Why doesnt a heavy object accelerate more than a light object when both are freely falling? Problem 12RCQ: What is the net force that acts on a 10-N falling object when it encounters 4 N of air resistance?... Problem 13RCQ: What two principal factors affect the force of air resistance on a falling object? Problem 14RCQ: What is the acceleration of a falling object that has reached its terminal velocity? Problem 15RCQ: If two objects of the same size fall through air at different speeds, which encounters the greater... Problem 16RCQ: Why does a heavy parachutist fall faster than a lighter parachutist who wears the same size... Problem 17RCQ: Earlier in this chapter, we treated force as a push or pull; now we say it is part of an... Problem 18RCQ: How many forces are required for a single interaction? Problem 19RCQ: When you push against a wall with your fingers, they bend because they experience a force. Identify... Problem 20RCQ: A boxer can hit a heavy bag with great force. Why cant he hit a sheet of tissue paper in midair with... Problem 21RCQ: State Newtons third law. Problem 22RCQ: Consider hitting a baseball with a bat. If we call the force of the bat against the ball the action... Problem 23RCQ: If the force that acts on a cannonball and the force that acts on the recoiling cannon from which it... Problem 24RCQ: Is it correct to say that action and reaction forces always act on different bodies? Defend your... Problem 25RCQ: If body A and body B are both within a system, can forces between them affect the acceleration of... Problem 26RCQ: In terms of forces, what is necessary to accelerate a system? Problem 27RCQ: Identify the force that propels a rocket into space. Problem 28RCQ: How does a helicopter get its lifting force? Problem 29RCQ: To what law of physics do we refer when we say you cannot touch without being touched? Problem 30RCQ: Which of Newtons laws focuses on inertia? Which on acceleration? Which on actionreaction? Problem 35PAC: In Chapter 1 acceleration is defined as a = vt. Show at that on an inclined plane, the acceleration... Problem 36PAC: In this chapter we learn that the cause of acceleration is given by Newton's second law: a = Fmnm.... Problem 37PAC: Knowing that a 1-kg object weighs 10 N. confirm that the acceleration of a 1-kg stone in free fall... Problem 38PAC: A simple rearrangement of Newton's second law gives Fnet = ma. Show that a net force of 84 N exerted... Problem 39TAS: A Honda Civic hybrid weighs about 2900 pounds, Calculate the weight of the car in newtons and its... Problem 40TAS: When two horizontal forces are exerted on the car in Problem 39.220 N forward and 180 N backward,... Problem 41TAS: A 12-kg astronaut recedes from her spacecraft by activating a small propulsion unit attached to her... Problem 42TAS: Madison pushes with a 160-N horizontal force on a 20-kg crate of coffee resting on a warehouse... Problem 43TAS: Sophia pushes with a 40-N horizontal force on a 4.0-kg box resting on a lab bench. The box slides... Problem 44TAS: A business jet of mass 30,000 kg takes off when the thrust for each of two engines is 30,000 N. Show... Problem 45TAS: A rocket of mass 100,000 kg undergoes an acceleration of 2 m/s2. Show that the net force acting on... Problem 46TAS: Calculate the horizontal force that must be applied to a 1-kg puck for it to accelerate on a... Problem 47TAS: Leroy, who has a mass of 100 kg, is skateboarding at 9.0 m/s when he smacks into a brick wall and... Problem 48TAS: For 3.0 s, Allison exerts a net force of 10.0 N on a 6.7-kg shopping cart that was initially at... Problem 49TAS: The heavyweight boxing champion of the world punches a sheet of paper in midair, bringing ii from... Problem 50TAS: Suzie Skydiver with her parachute has a mass of 50 kg. (a) Before opening her chute, what force of... Problem 51TAS: If you stand next to a wall on a frictionless skateboard and push the wall with a force of 40 N, how... Problem 52TAS: A force Facts in the forward direction on a cart of mass m. A friction force f opposes this motion.... Problem 53TAS: A firefighter of mass 80 leg slides down a vertical pole with an acceleration of 4 m/s2. Show that... Problem 54TAS: A rock bands tour bus, mass M, is accelerating away from a stop sign at rate a when a piece of heavy... Problem 55TAR: Boxes of various masses are on a friction-free level table. (a) Rank, from greatest to least, the... Problem 56TAR: In cases A, B, and C, the crate is in equilibrium (no acceleration). Rank, from greatest to least,... Problem 57TAR: Consider a 100-kg box of tools in the locations A, B, and C. (a) Rank, from greatest to least, the... Problem 58TAR: Three parachutists, A, B, and C, have reached terminal velocity at the same altitude. (a) Rank their... Problem 59TAR: The strong man is pulled in the three situations shown. Rank, from least to greatest, the amount of... Problem 60E: The Moon travels in a nearly circular path around Earth. If somehow gravitation between Earth and... Problem 61E: To pull a wagon across a lawn at constant velocity, you must exert a steady force. Reconcile this... Problem 62E: Your empty hand is not hurt when it bangs lightly against a wall. Why does your hand hurt when it... Problem 63E: Why is a massive cleaver more effective for chopping vegetables than a lighter knife of the same... Problem 64E: Aristotle claimed that the speed of a falling object depends on its weight. We now know that all... Problem 65E: What is the net force acting on a 1-kg ball in free fall? What is the net force if it encounters 2 N... Problem 66E: As you leap upward from the ground, how does the force that you exert on the ground compare with... Problem 67E: "It's not the fall that hurts you; it's the sudden stop." Translate this common saying into Newton's... Problem 68E: For each of the following interactions, identify the action and reaction forces, (a) A hammer... Problem 69E: You hold an apple over your head. (a) Identify all the forces acting on the apple and their reaction... Problem 70E: What is the net force on an apple that weighs 1 N when you hold it at rest above your head? What is... Problem 71E: Why does a cat that falls from the top of a 50-story building hit a safety net below no faster than... Problem 72E: Free fall is motion in which gravity is the only force acting. (a) Explain why a skydiver who has... Problem 73E: How does the weight of a falling body compare with the air resistance it encounters just before it... Problem 74E: You tell your friend that the acceleration of a skydiver decreases as falling progresses. What is... Problem 75E: We know that Earth pulls on the Moon. Does it follow that the Moon also pulls on Earth? Problem 76E: A friend says that Al cannot push on the tree unless the tree pushes back on her, and another friend... Problem 77E: Why can a boxer hit a heavy opponent harder for the same punch than she or he can hit a light... Problem 78E: When you stand on a floor, does the floor exert an upward force against your feet? How much force... Problem 79E: Why can you exert greater force on the pedals of a bicycle if you pull upon the handlebars? Problem 80E: The strong man will push apart the two initially stationary freight cars of equal mass before he... Problem 81E: Suppose two carts, one twice as massive as the other, fly apart when the compressed spring that... Problem 82E: Two 100-N weights are attached to a spring scale as shown. Does the scale read 0 N, 100 N, or 200 N,... Problem 83E Problem 84E: When the athlete holds the barbell overhead, the reaction force is the weight of the barbell on his... Problem 85E: Consider the two forces acting on the person who stands stillnamely, the downward pull of gravity... Problem 86E: If a Mack truck and a motorcycle have a head-on collision, upon which vehicle is the impact force... Problem 87E: Two people of equal mass attempt a tug-of-war with a 12-m rope while standing on frictionlees ice.... Problem 88E: Suppose that one of the people in Exercise 87 has twice the mass of the other. How far does each... Problem 89E: Which team wins in a tug-of-war: the team that pulls harder on the rope, or the team that pushes... Problem 90E: The photo shows Steve Hewitt and his daughter Gretchen. Is Gretchen touching her dad, or is he... Problem 91E: When your car moves along the highway at constant velocity, the net force on it is zero. Why, then,... Problem 92E: The auto in the sketch moves forward as the brakes are applied. A bystander says that during the... Problem 93E: A racing car travels along a straight raceway at a constant velocity of 200 km/h. What horizontal... Problem 94E: If it were not for air resistance, would it be dangerous to go outdoors on rainy days? Defend your... Problem 95E: When you toss a coin upward, what happens to its velocity while it is ascending? What happens to its... Problem 96DQ: Discuss whether or not a stick of dynamite contains force. Similarly, does a fist contain forcer A... Problem 97DQ: In an orbiting space craft, you are handed two identical closed boxes, one filled with sand and the... Problem 98DQ: Each of the vertebrae forming your spine is separated from its neighbors by discs of elastic tissue.... Problem 99DQ: Before the time of Galileo and Newton, many learned scholars thought that a stone dropped from the... Problem 100DQ: The opening photo in this chapter shows a favorite demonstration of author Paul Hewitt lying on his... Problem 101DQ: Consider a ball at rest in the middle of a toy wagon. When the wagon is pulled forward, the ball... Problem 102DQ: If youre in a car at rest that gets hit from behind, you can suffer a serious neck injury called... Problem 103DQ: Why do you lurch forward in a bus that suddenly slows down? Why do you lurch backward when it picks... Problem 104DQ: Suppose that youre in a moving car and the engine stops running. You step on the brakes and slow the... Problem 105DQ: A rocket becomes progressively easier to accelerate as it travels through space. Why? (Hint: About... Problem 106DQ: If you drop an object, its acceleration toward the ground is 10 m/s2. If you throw it down instead,... Problem 107DQ: Can you think of a reason why the acceleration of the object thrown downward through the air in... Problem 108DQ: You throw a ball straight upward. Compared with its initial speed when thrown, how fast does it... Problem 109DQ: A couple of your friends say that before a falling body reaches terminal velocity, it gains speed... Problem 110DQ: How does the terminal speed of a parachutist before opening a parachute compare to the terminal... Problem 111DQ: How does the gravitational force on a falling body compare with the air resistance it encounters... Problem 112DQ: If and when Galileo dropped two balls from the top of the Leaning Tower of Pisa, air resistance was... Problem 113DQ: This is a scenario common to many physics students: You push a heavy car by hand. The car, in turn,... Problem 114DQ: A fanner urges his horse to pull a wagon. The horse refuses, saying that to try would be futile, for... Problem 115DQ: When Marie exerts a horizontal force of 200 N to slide a table across a floor at constant velocity,... Problem 116DQ: Two equal-mass blocks are connected by a length of string. One block is placed at rest on a very... Problem 117DQ: The bricks in this road were originally straight. Describe evidence for tires pushing the bricks in... Problem 118DQ: Ken and Joanne are astronauts floating some distance apart in space. They are joined by a safety... Problem 119DQ: Can a clog wag its tail without the tail in turn wagging the dog? (Consider a dog with a relatively... Problem 120DQ: If you simultaneously drop a pair of tennis balls from the top of a building, they strike the ground... Problem 1RAT: If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in (a) a curved... Problem 2RAT: A ball rolls down a curved ramp as shown. As its speed increases, its rate of gaining speed (a)... Problem 3RAT: A block of ice sliding without friction down an icy flat incline gains speed, while its acceleration... Problem 4RAT: The reason why a 10-kg rocks falls no faster than a 5-kg rock in free falls is that the (a) 10-kg... Problem 5RAT: As mass is added to a cart pushed by a constant force, its acceleration (a) remains constant. (b)... Problem 6RAT: The amount of air resistance that acts on a wingsuit flyer (and a flying squirrel) depends on the... Problem 7RAT: You drop a pillow off the edge of the administration building on your campus. While the pillow is... Problem 8RAT: Alex pulls on the end of a spring attached to a wall. The reaction to Alexs pull on the spring is... Problem 9RAT: The amount of force with which a boxers punch lands depends mainly on the (a) physical condition of... Problem 10RAT: The force that propels a rocket is provided by (a) gravity. (b) Newtons laws of motion. (c) its... format_list_bulleted