Physics (5th Edition)
5th Edition
ISBN: 9780321976444
Author: James S. Walker
Publisher: PEARSON
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Textbook Question
Chapter 7.2, Problem 2EYU
Enhance Your Understanding
(Answers given at the end of the chapter)
1. An object has an initial kinetic energy of 100 J. A few minutes later, after a single external force has acted on the object Its kinetic energy is 200 J. Is the work done by the force positive, negative, or zero? Explain
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Students have asked these similar questions
Please answer in Essay Form. Write legibly. Thank you
1. Explain in detail when work done is positive and work done is negative and under what circumstances (if any) is no work done (zero) on a moving object even though a net force acts on it?
2. One sometimes speaks of the "direction of time", evolving from past to future. Does this mean that time is a vector quantity? Explain your reasoning.
3. The acceleration of a certain moving object is constant in magnitude and direction. Must the path of the object is a straight-line? If not, give an example.
Please answer all components of the question:
An amusement park ride uses magnets to accelerate a 500 kg car to an initial speed of 15 m/s. The roller coaster then begins to coast up a hill.
a) What energy conversion takes place as the car goes up the hill? Justify
b) What is the maximum height that the car can attain without receiving additional energy? Show your work.
c) If the car loses 10,000 J of energy to friction, what height will it attain instead? Show your work.
Write your solution and answer correctly.
1. After a leaf falls from a tree, an apple falls next. If the apple has a potential energy of 97 J and a kinetic energy of 420 J, how much energy is present on the apple?
Chapter 7 Solutions
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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