Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
4th Edition
ISBN: 9780134110684
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 slab of mass m1 40 kg rests on a frictionless floor, and a block of mass m2 10 kg rests on top of the slab. Between block and slab, the coefficient of static friction is 0.60, and the coefficient of kinetic friction is 0.40.A horizontal force of magnitude 100 N begins to pull directly on the block, as shown. In unit-vector notation, what are the resulting accelerations of (a) the block and (b) the slab?
Chapter 7 Solutions
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (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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