Physics (5th Edition)
5th Edition
ISBN: 9780321976444
Author: James S. Walker
Publisher: PEARSON
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Textbook Question
Chapter 7, Problem 11PCE
Predict/Calculate To clean a floor, a janitor pushes on a mop handle with a force of 50.0 N. (a) If the mop handle is at an angle of 55° above the horizontal how much work is required to push the mop 0.50 m? (b) If the angle the mop handle makes with the horizontal is increased to 65°, does the work done by the janitor increase, decrease, or stay the same? Explain.
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Physics (5th Edition)
Ch. 7.1 - Enhance Your Understanding (Answers given at the...Ch. 7.2 - Enhance Your Understanding (Answers given at the...Ch. 7.3 - As an object moves along the positive x axis the...Ch. 7.4 - Enhance Your Understanding (Answers given at the...Ch. 7 - Is it possible to do work on an object that...Ch. 7 - A friend makes the statement, Only the total force...Ch. 7 - A friend makes the statement, A force that is...Ch. 7 - The net work done on a certain object is zero What...Ch. 7 - Give an example of a frictional force doing...Ch. 7 - A ski boat moves with constant velocity Is the net...
Ch. 7 - A package rests on the floor of an elevator that...Ch. 7 - An object moves with constant velocity Is it safe...Ch. 7 - Engine 1 does twice the work of engine 2. Is it...Ch. 7 - Engine 1 produces twice the power of engine 2. Is...Ch. 7 - A pendulum bob swings from point I to point II...Ch. 7 - A pendulum bob swings from point II to point III...Ch. 7 - A farmhand pushes a 26-kg bale of hay 3.9 m across...Ch. 7 - Children in a tree house lift a small dog in a...Ch. 7 - Early one October, you go to a pumpkin patch to...Ch. 7 - The coefficient of kinetic friction between a...Ch. 7 - BIO Peristaltic Work The human snail intestine...Ch. 7 - Predict/Calculate A tow rope, parallel to the...Ch. 7 - A child pulls a friend in a little red wagon with...Ch. 7 - A 57-kg packing crate is pulled with constant...Ch. 7 - Predict/Calculate To clean a floor, a janitor...Ch. 7 - A small plane tows a glider at constant speed and...Ch. 7 - As a snowboarder descends a mountain slope,...Ch. 7 - A young woman on a skateboard is pulled by a rope...Ch. 7 - To keep her dog from running away while she talks...Ch. 7 - Water skiers often ride to one side of the center...Ch. 7 - A pitcher throws a ball at 90 mi/h and the catcher...Ch. 7 - How much work is needed for a 73 kg runner to...Ch. 7 - Skylabs Reentry When Skylab reentered the Earths...Ch. 7 - Predict/Calculate A 9.50-g bullet has a speed of...Ch. 7 - The energy required to increase the speed of a...Ch. 7 - Predict/Explain The work W0 accelerates a car...Ch. 7 - Car A has a mass m and a speed u, car B has a mass...Ch. 7 - Predict/Calculate A 0.14-kg pinecone falls 16 m to...Ch. 7 - In the previous problem (a) how much work was done...Ch. 7 - At t = 1.0s, a 0.55-kg object is tailing with a...Ch. 7 - After hitting a long fly ball that goes over the...Ch. 7 - Predict/Calculate A 1100-kg car coasts on a...Ch. 7 - A 65-kg bicyclist rides his 8 8-kg bicycle with a...Ch. 7 - A block of mass m and speed U collides with a...Ch. 7 - A spring with a force constant of 3.5 104 N/m is...Ch. 7 - Initially sliding with a speed of 4.1 m/s, a...Ch. 7 - The force shown in Figure 7-21 moves an object...Ch. 7 - An object is acted on by the force shown in Figure...Ch. 7 - To compress spring 1 by 0 20 m takes 150 J of...Ch. 7 - Predict/Calculate It takes 180 J of work to...Ch. 7 - The force shown in Figure 7-22 acts on a 1.3-kg...Ch. 7 - A block is acted on by a force that varies as (2.0...Ch. 7 - Section 7-4 Power 42 CE Fore F1 does 5 J of work...Ch. 7 - BIO Climbing the Empire State Building A new...Ch. 7 - Calculate the power output of a 14-mg fly as it...Ch. 7 - An ice cube is placed in a microwave oven. Suppose...Ch. 7 - Your car produces about 34 kw of power to maintain...Ch. 7 - You raise a bucket of water from the bottom of a...Ch. 7 - BIO Salmon Migration As Chinook salmon swim...Ch. 7 - In order to keep a leaking ship from sinking, it...Ch. 7 - Predict/Calculate A kayaker paddles with a power...Ch. 7 - BIO Human-Powered Flight Human-powered aircraft...Ch. 7 - Predict/Calculate Beating to Windward A sailboat...Ch. 7 - Predict/Calculate A grandfather clock is powered...Ch. 7 - Prob. 54PCECh. 7 - CE As the three small sailboats shown in Figure...Ch. 7 - CE Predict/Explain A car is accelerated by a...Ch. 7 - CE Car 1 has four limes the mass of car 2, but...Ch. 7 - BIO Muscle Cells Biological muscle cells can be...Ch. 7 - A small motor runs a lift that raises a load of...Ch. 7 - You push a 67-kg box across a door where the...Ch. 7 - A 1300-kg elevator is lifted at a constant speed...Ch. 7 - CE The work W0 is required to accelerate a car...Ch. 7 - After a tornado a 0.55-g straw was found embedded...Ch. 7 - You throw a glove straight upward to celebrate a...Ch. 7 - The water skier in Figure 7-20 is at an angle of...Ch. 7 - Predict/Calculate A sled with a mass of 5.80 kg is...Ch. 7 - Predict/Calculate A 0.19-kg apple falls from a...Ch. 7 - A boy pulls a bag of baseball bats across a ball...Ch. 7 - At the instant it leaves the players hand after a...Ch. 7 - The force shown in Figure 7-25 acts on an object...Ch. 7 - A Compound Bow A compound bow in archery allows...Ch. 7 - A Compound Versus a Simple Bow The compound bow in...Ch. 7 - Calculate the power output of a 0.42-g spider as...Ch. 7 - Cookie Power To make a batch of cookies, you mix...Ch. 7 - Predict/Calculate A pitcher accelerates a 0.14-kg...Ch. 7 - BIO Brain Power The human brain consumes about 22...Ch. 7 - Meteorite On October 9, 1992, a 27-pound meteorite...Ch. 7 - BIO Powering a Pigeon A pigeon in flight...Ch. 7 - Springs in Series Two springs, with force...Ch. 7 - Springs in Parallel Two springs, with force...Ch. 7 - A block rests on a horizontal frictionless...Ch. 7 - BIO Microraptor gui: The Biplane Dinosaur The...Ch. 7 - BIO Microraptor gui: The Biplane Dinosaur The...Ch. 7 - BIO Microraptor gui: The Biplane Dinosaur The...Ch. 7 - BIO Microraptor gui: The Biplane Dinosaur The...Ch. 7 - Referring to Figure 7-15 Suppose the block has a...Ch. 7 - Predict/Calculate Referring to Figure 7-15 In the...Ch. 7 - Predict/Calculate Referring 10 Example 7-15...
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Mechanical work done (GCSE Physics); Author: Dr de Bruin's Classroom;https://www.youtube.com/watch?v=OapgRhYDMvw;License: Standard YouTube License, CC-BY