Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
4th Edition
ISBN: 9780133942651
Author: Randall D. Knight (Professor Emeritus)
Publisher: PEARSON
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Chapter 7, Problem 19EAP
A woman living in a third-story apartment is moving out. Rather than carrying everything down the stairs, she decides to pack her belongings into crates, attach a frictionless pulley to her balcony railing, and lower the crates by rope. How hard must she pull on the horizontal end of the rope to lower a 25 kg crate at steady speed?
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A traveler at an airport takes an escalator up one floor as in the figure below. The moving staircase would itself carry him upward with vertical velocity component v between entry and exit points separated by height h. However, while the escalator is moving, the hurried traveler climbs the
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energy =
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Chapter 7 Solutions
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
Ch. 7 - You find yourself in the middle of a frozen lake...Ch. 7 - How does a sprinter sprint? What is the forward...Ch. 7 - How does a rocket take off? What is the upward...Ch. 7 - How do basketball players jump straight up into...Ch. 7 - A mosquito collides head-on with a car traveling...Ch. 7 - A mosquito collides head-on with a car traveling...Ch. 7 - A small car is pushing a large truck. They are...Ch. 7 - A very smart 3-year-old child is given a wagon for...Ch. 7 - Teams red blue are having a tug-of-war. According...Ch. 7 - Will hanging a magnet in front of the iron cart in...
Ch. 7 - FIGURE Q7.11 shows two masses at rest. The string...Ch. 7 - FIGURE Q7.12 shows two masses at rest. The string...Ch. 7 - The hand in FIGURE Q7.13 is pushing on the back of...Ch. 7 - A and B in FIGURE Q7.14 are connected by a...Ch. 7 - In case a in FIGURE Q7.15, block A is accelerated...Ch. 7 - For Exercises 1 through 5: a. Draw an interaction...Ch. 7 - For Exercises 1 through 5: a. Draw an interaction...Ch. 7 - For Exercises I through 5: a. Draw an interaction...Ch. 7 - For Exercises 1 through 5: a. Draw an interaction...Ch. 7 - For Exercises 1 through 5: a. Draw an interaction...Ch. 7 - a. How much force does an 80 kg astronaut exert on...Ch. 7 - Block B in FIGURE EX7.7 rests on a surface for...Ch. 7 - A 1000 kg car pushes a 2000 kg truck that has a...Ch. 7 - with masses of 1 kg, 2 kg, and 3 kg are lined up...Ch. 7 - A 3000 kg meteorite falls toward the earth. What...Ch. 7 - The foot of a 55 kg sprinter is on the ground for...Ch. 7 - A steel cable lying flat on the floor drags a 20...Ch. 7 - An 80 kg spacewalking astronaut pushes off a 640...Ch. 7 - The sled dog in FIGURE EX7.14 drags sleds A and B...Ch. 7 - Two-thirds of the weight of a 1500 kg car rests on...Ch. 7 - FIGURE EX7.16 shows two 1.0 kg blocks connected by...Ch. 7 - What is the tension in the rope of Figure EX7.17?...Ch. 7 - A 2.0-m-long, 500 g rope pulls a 10 kg block of...Ch. 7 - A woman living in a third-story apartment is...Ch. 7 - Two blocks are attached to opposite ends of a...Ch. 7 - The cable cars in San Francisco are pulled along...Ch. 7 - A 2.0 kg rope hangs from the ceiling. What is the...Ch. 7 - A mobile at the art museum has a 2.0 kg steel cat...Ch. 7 - The 1.0 kg block in FIGURE EX7.24 is tied to the...Ch. 7 - The 100 kg block in FIGURE EX7.25 takes 6.0 s to...Ch. 7 - FIGURE P7.26 shows two strong magnets on opposite...Ch. 7 - FIGURE P7.27 shows a 6.0 N force pushing two...Ch. 7 - 28. A rope of length L and mass m is suspended...Ch. 7 - Prob. 29EAPCh. 7 - 30. A Federation starship (2.0 × 106 kg) uses its...Ch. 7 - Your forehead can withstand a force of about 6.0...Ch. 7 - Bob, who has a mass of 75 kg, can throw a 500 g...Ch. 7 - Two packages at UPS start sliding down the 20°...Ch. 7 - The two blocks in FIGURE P7.34 are sliding down...Ch. 7 - The coefficient of static friction is 0.60 between...Ch. 7 - The block of mass M in FIGURE P7.36 slides on a...Ch. 7 - The 10.2 kg block in FIGURE P7.37 is held in place...Ch. 7 - The coefficient of kinetic friction between the...Ch. 7 - FIGURE P7.39 shows a block of mass m resting on a...Ch. 7 - A4.0 kg box is on a frictionless 35° slope and is...Ch. 7 - Prob. 41EAPCh. 7 - The 2000 kg cable car shown in FIGURE P7.42...Ch. 7 - The century-old ascensores in Valparaiso, Chile,...Ch. 7 - A 3200 kg helicopter is flying horizontally. A 250...Ch. 7 - A house painter uses the chair-and-pulley...Ch. 7 - A long, 1.0 kg rope hangs from a support that...Ch. 7 - Prob. 47EAPCh. 7 - Prob. 48EAPCh. 7 - Find an expression for the magnitude of the...Ch. 7 - Prob. 50EAPCh. 7 - Prob. 51EAPCh. 7 - Prob. 52EAPCh. 7 - The lower block in FIGURE CP7.53 is pulled on by a...Ch. 7 - Prob. 54EAPCh. 7 - Prob. 55EAPCh. 7 - A 40-cm-diameter, 50-cm-tall, 15 kg hollow...Ch. 7 - 57. FIGURE CP7.57 shows a 200 g hamster sitting on...Ch. 7 - Prob. 58EAP
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