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
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
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?
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
A car has a mass of 1750 kg. If the driver applies the brakes while on a gravel road, the maximum friction force that the tires can provide without skidding is about 6500 N. If the car is moving at 22 m/s, what is the shortest distance in which the car can stop safely?
A fisherman has caught a very large, 5.0 kg fish from a dock that is 2.0 m above the water. He is using lightweight fishing line that will break under a tension of 54 N or more. He is eager to get the fish to the dock in the shortest possible time. If the fish is at rest at the water’s surface, what’s the least amount of time in which the fisherman can raise the fish to the dock without losing it?
Sammy is doing a strength testing session on the turf in preparation for the upcoming basketball season. Sammy's mass is 55 kg and she is trying to push a 105 kg sled across the artificial turf outside on Raymond Field. The coefficient of static friction between the sled and the turf is 0.3. If Sammy pushes only horizontally against the sled, how much force must she push with to just initiate movement of the sled?
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
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- Two blocks, each of mass m = 3.50 kg, are hung from the ceiling of an elevator as in Figure P4.33. (a) If the elevator moves with an upward acceleration a of magnitude 1.60 m/s2, find the tensions T1 and T2 in the upper and lower strings. (b) If the strings can withstand a maximum tension of 85.0 N, what maximum acceleration can the elevator have before a string breaks? Figure P4.33 Problems 33 and 34.arrow_forwardA 11 kg block rests on a 26 degree inclined frictionless surface and is attached by a light string to a 30 kg hanging mass where the string passes over a massless frictionless pulley. If g = 9.8 m/s2, what is the tension in the connecting string?arrow_forwardTwo workers are sliding a 300 kg crate across the floor. One worker pushes forward on the crate with a force of 380 N while the other pulls in the same direction with a force of 350 N using a rope connected to the crate. Both forces are horizontal, and the crate slides with a constant speed. What is the crate’s coefficient of kinetic friction on the floor?arrow_forward
- A person whose weight is 516 N is being pulled up vertically by a rope from the bottom of a cave that is 30.5 m deep. The maximum tension that the rope can withstand without breaking is 593 N. What is the shortest time, starting from rest, in which the person can be brought out of the cave?arrow_forwardA football coach sits on a sled while two of his players build their strength by dragging the sled across the field with ropes. The friction force on the sled is 1400 N and the angle between the two ropes is 50 degrees. Assume both players pull with the same force. How hard must each player pull to drag the coach at a steady 2.0 m/s?arrow_forwardA box of oranges with a weight of 78 N is being pushed across a horizontal floor. As it moves, it is slowing at a constant rate of 0.90 m/s each second. The push force has a horizontal component of 20 N and a vertical component of 25 N downward. Calculate the coefficient of kinetic friction between the box and floor. μk= ?arrow_forward
- An 80.0 kg mail bag hangs by a vertical rope 3.7 m long. A postal worker then displaces the bag to a position 2.5 meters sideways from its original position, always keeping the rope taut. What horizontal force is necessary to hold the bag in the new position?arrow_forwardThe cable supporting a 2100 kg elevator can withstand a maximum tension of 21000 N. What is the maximum upward acceleration of the elevator can the cable withstand? (Use g = 9.8 m/s²) O 0.20 m/s² O 0.78 m/s² O 9.8 m/s² O 10.0 m/s² O none of the choicesarrow_forwardTwo blocks A and B with mA = 1.1 kg and mB = 0.88 kg are connected by a string of negligible mass. They rest on a frictionless horizontal surface. You pull on block A with a horizontal force of 6.7 N. How will the tension in the string be affected if mA is decreased?arrow_forward
- You find it takes 190 N of horizontal force to move an unloaded pickup truck along a level road at a speed of 2.4 m/s . You then load up the pickup and pump up its tires so that its total weight increases by 42%while the coefficient of rolling friction decreases by 19%. Now what horizontal force will you need to move the pickup along the same road at the same speed? The speed is low enough that you can ignore air resistance..arrow_forwardYou are pulling a child through the snow on a sled by pulling on a rope that makes a 35°35° angle with the horizontal. The mass of the child and sled together is 20 kg. There is a 50 N force of friction opposing the motion. What is the tension in the rope when you pull the child and sled at a constant 3.0m/s?arrow_forwardA 1100-kg elevator is rising and its speed is increasing at 3.0 m/s2. The tension in the elevator cable is: Group of answer choices 1100 N 11000 N 7500 N 3300 N 14000 Narrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
Glencoe Physics: Principles and Problems, Student...
Physics
ISBN:9780078807213
Author:Paul W. Zitzewitz
Publisher:Glencoe/McGraw-Hill
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
Conservative and Non Conservative Forces; Author: AK LECTURES;https://www.youtube.com/watch?v=vFVCluvSrFc;License: Standard YouTube License, CC-BY