Essential University Physics: Volume 1 (3rd Edition)
3rd Edition
ISBN: 9780321993724
Author: Richard Wolfson
Publisher: PEARSON
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Textbook Question
Chapter 6, Problem 89P
You’re an expert witness in a medical malpractice lawsuit. A hospital patient’s leg slipped off a stretcher and his heel hit the floor. The defense attorney for the hospital claims the leg, with mass 8 kg, hit the floor with a force equal to the weight of the leg—about 80 N—and any damage was due to a prior injury. You argue that the leg and heel dropped freely for 0.7 m, then hit the floor and stopped in 2 cm. What do you tell the jury about the force on the heel?
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The picture is a hint that they provided
(a) Calculate the force needed to bring a 850 kg car to rest from a speed of 95.0 km/h in a distance of 105 m (a fairly typical distance for a nonpanic stop). N(b) Suppose instead the car hits a concrete abutment at full speed and is brought to a stop in 2.00 m. Calculate the force exerted on the car and compare it with the force found in part (a), i.e. find the ratio of the force in part(b) to the force in part(a). (force in part (b) / force in part (a))
Chapter 6 Solutions
Essential University Physics: Volume 1 (3rd Edition)
Ch. 6.2 - Two objects are each displaced the same distance,...Ch. 6.3 - Three forces have magnitudes in newtons that are...Ch. 6.4 - For each situation, tell whether the net work done...Ch. 6 - Give two examples of situations in which you might...Ch. 6 - If the scalar product of two nonzero vectors is...Ch. 6 - Must you do work to whirl a ball around on the end...Ch. 6 - If you pick up a suitcase and put it down, how...Ch. 6 - You want to raise a piano a given height using a...Ch. 6 - Does the gravitational force of the Sun do work on...Ch. 6 - A pendulum bob swings back and forth on the end of...
Ch. 6 - Does your cars kinetic energy change if you drive...Ch. 6 - A watt-second is a unit of what quantity? Relate...Ch. 6 - A truck is moving northward at 55 mi/h. Later, its...Ch. 6 - Is it possible for you to do work on an object...Ch. 6 - How much work do you do as you exert a 75-N force...Ch. 6 - If the coefficient of kinetic friction is 0.21,...Ch. 6 - A crane lifts a 650-kg beam vertically upward 23 m...Ch. 6 - The worlds highest waterfall, the Cherun-Meru in...Ch. 6 - A meteorite plunges to Earth, embedding itself 75...Ch. 6 - An elevator of mass m rises a vertical distance h...Ch. 6 - Prob. 19ECh. 6 - Find the work done by a force F = 1.8 + 2.2 N as...Ch. 6 - To push a stalled car, you apply a 470-N force at...Ch. 6 - Find the total work done by the force shown in...Ch. 6 - How much work does it take to stretch a spring...Ch. 6 - Uncompressed, the spring for an automobile...Ch. 6 - You do 8.5 J of work to stretch a spring with k =...Ch. 6 - Spider silk is a remarkable elastic material. A...Ch. 6 - Whats the kinetic energy of a 2.4105-kg airplane...Ch. 6 - Prob. 28ECh. 6 - At what speed must a 950-kg subcompact car be...Ch. 6 - A 60-kg skateboarder comes over the top of a hill...Ch. 6 - After a tornado, a 0.50-g drinking straw was found...Ch. 6 - From what height would you have to drop a car for...Ch. 6 - A typical human diet is 2000 calories per day,...Ch. 6 - A horse plows a 200-m-long furrow in 5.0 min,...Ch. 6 - A typical car battery stores about 1 kWh of...Ch. 6 - A sprinter completes a 100-m dash in 10.6 s. doing...Ch. 6 - How much work can a 3.5-hp lawnmower engine do in...Ch. 6 - A 75-kg long-jumper takes 3.1 s to reach a prejump...Ch. 6 - Estimate your power output as you do deep knee...Ch. 6 - In midday sunshine, solar energy strikes Earth at...Ch. 6 - It takes about 20 kJ to melt an ice cube. A...Ch. 6 - Prob. 42ECh. 6 - You slide a box of books at constant speed up a 30...Ch. 6 - Two people push a stalled car at its front doors,...Ch. 6 - Youre at the gym, doing arm raises. With each rep....Ch. 6 - A locomotive does 7.9 1011 J of work in pulling a...Ch. 6 - You pull a box 23 in horizontally, using the rope...Ch. 6 - Prob. 48PCh. 6 - (a) Find the scalar product of the vectors a + b...Ch. 6 - Looking to cut costs, the airline you work for...Ch. 6 - How much work does a force F = 67 + 23 + 55k N do...Ch. 6 - A force F Facts in the x-direction, its magnitude...Ch. 6 - A certain amount of work is required to stretch...Ch. 6 - A force with magnitude F = a x acts in the...Ch. 6 - The force exerted by a rubber band is given...Ch. 6 - You put your little sister (mass m) on a swing...Ch. 6 - Two unknown elementary particles pass through a...Ch. 6 - A tractor tows a plane from its airport gate,...Ch. 6 - E. coli bacteria swim by means of flagella that...Ch. 6 - On February 15, 2013, an asteroid moving at 19...Ch. 6 - An elevator ascends from the ground floor to the...Ch. 6 - Youre asked to assess the reliability of a nuclear...Ch. 6 - A force pointing in the x-direction is given by F...Ch. 6 - A force pointing in the x-direction is given by F...Ch. 6 - Two vectors have equal magnitude, and their scalar...Ch. 6 - At what rate can a half-horsepower well pump...Ch. 6 - The rate at which the United States imports oil,...Ch. 6 - By measuring oxygen uptake, sports physiologists...Ch. 6 - Youre writing performance specifications for a new...Ch. 6 - A 1400-kg car ascends a mountain road at a steady...Ch. 6 - You do 2.2 kJ of work pushing a 78-kg trunk at...Ch. 6 - (a) Find the work done in lifting 1 L of blood...Ch. 6 - (a) What power is needed to push a 95-kg crate at...Ch. 6 - You mix flour into bread dough, exerting a 45-N...Ch. 6 - A machine does work at a rate given by P = ct2,...Ch. 6 - A typical bumblebee has mass 0.25 mg. It beats its...Ch. 6 - Youre trying to decide whether to buy an...Ch. 6 - Your friend does five reps with a barbell, on each...Ch. 6 - A machine delivers power at a decreasing rate P =...Ch. 6 - A locomotive accelerates a freight train of total...Ch. 6 - A force given by F = b/x acts in the x-direction,...Ch. 6 - Youre assisting a cardiologist in planning a...Ch. 6 - Youre an engineer for a company that makes...Ch. 6 - You push an object of mass m slowly, partway up a...Ch. 6 - A particle moves from the origin to the point x =...Ch. 6 - Repeat Problem 85 for the following cases: (a) the...Ch. 6 - The worlds fastest elevator, in Taiwans Taipei 101...Ch. 6 - An experimental measurement of the force required...Ch. 6 - Youre an expert witness in a medical malpractice...Ch. 6 - The energy in a batted baseball comes from the...Ch. 6 - The energy in a batted baseball comes from the...Ch. 6 - The energy in a batted baseball comes from the...Ch. 6 - The energy in a batted baseball comes from the...
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