Essential University Physics
4th Edition
ISBN: 9780134988559
Author: Wolfson, Richard
Publisher: Pearson Education,
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
Chapter 2, Problem 70P
You’re speeding at 85 km/h when you notice that you’re only 10 m behind the car in front of you, which is moving at the legal speed limit of 60 km/h. You slam on your brakes, and your car negatively accelerates at 4.2 m/s2. Assuming the other car continues at constant speed, will you collide? If so, at what relative speed ? If not, what will be the distance between the cars at their closest approach?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
You’re speeding at 85 km/h when you notice that you’re only 10 m behind the car in front of you, which is moving at the legal speed limit of 60 km/hr. You slam on your brakes, and your car negatively accelerates at 4.2 m/s2 . Assuming the other car continues at constant speed, will you collide? If so, at what relative speed? If not, what will be the distance between the cars at their closest approach?
A jeepney and a train are moving together along parallel paths at 30.0 m/s, with the jeepney adjacent to the rear of the train. The jeepney driver sees the traffic light turn red, so he accelerates at -2.50 m/s2, and then let his jeepney come to rest. The jeepney is at rest for 50.0 s, and then accelerates at 2.50 m/s2 to go back to a speed of 30.0 m/s. Assuming that the speed of the train remained constant at 30.0 m/s, how far is the jeepney from the rear of the train when the jeepney reaches a speed of 30.0 m/s?
Christopher watches a stick float downstream in a river and notices that it moves 15 m [El in a time of 2.5 x 10' s. His friend, John, is starting on the south side of the river and is going to swim across. In still water, John knows that he can swim with a speed of 1.2 m/s, relative to the water.
a) What is John's velocity relative to the shore?
b) If the river is 1.5 km wide, how long will it take John to cross the river?
c) How far downstream will be land?
Chapter 2 Solutions
Essential University Physics
Ch. 2.1 - We just described three trips from Houston to Des...Ch. 2.2 - The figures show position-versus-time graphs for...Ch. 2.3 - An elevator is going up at constant speed, slows...Ch. 2.5 - Standing on a roof, you simultaneously throw one...Ch. 2.6 - The graph shows acceleration versus time for three...Ch. 2 - Under what conditions are average and...Ch. 2 - Does a speedometer measure speed or velocity?Ch. 2 - You check your odometer at the beginning of a days...Ch. 2 - Consider two possible definitions of average...Ch. 2 - Is it possible to be at position x = 0 and still...
Ch. 2 - Is it possible to have zero velocity and still be...Ch. 2 - If you know the initial velocity v0 and the...Ch. 2 - In which of the velocity-versus-time graphs shown...Ch. 2 - If you travel in a straight line at 50 km/h for 1...Ch. 2 - If you travel in a straight line at 50 km/h for 50...Ch. 2 - In 2009, Usain Bolt of Jamaica set a world record...Ch. 2 - Earth’s diameter is approximately 8000 miles....Ch. 2 - Starting front home, you bicycle 24 km north in...Ch. 2 - The Voyager 1 spacecraft is expected to continue...Ch. 2 - Prob. 15ECh. 2 - Whats the conversion factor from meters per second...Ch. 2 - On a single graph, plot distance versus time for...Ch. 2 - For the motion plotted in Fig. 2.15, estimate (a)...Ch. 2 - A model rocket is launched straight upward. Its...Ch. 2 - You’re driving at the 50 km/h speed limit when you...Ch. 2 - Starting from rest, a subway train first...Ch. 2 - Prob. 22ECh. 2 - An egg drops from a second-story window, taking...Ch. 2 - An airplanes takeoff speed is 320 km/h. If its...Ch. 2 - ThrustSSC, the worlds first supersonic car,...Ch. 2 - Youre driving at 70 km/h when you apply constant...Ch. 2 - Prob. 27ECh. 2 - Prob. 28ECh. 2 - Prob. 29ECh. 2 - Starting from rest, a car accelerates at a...Ch. 2 - A car moving initially at 50 mi/h begins slowing...Ch. 2 - In a medical X-ray tube, electrons are accelerated...Ch. 2 - Californias Bay Area Rapid Transit System (BART)...Ch. 2 - Youre driving at speed v0 when you spot a...Ch. 2 - Prob. 35ECh. 2 - Your friend is sitting 6.5 m above you on a tree...Ch. 2 - A model rocket leaves the ground, heading straight...Ch. 2 - A foul ball leaves the bat going straight up at 23...Ch. 2 - A Frisbee is lodged in a tree 6.5 m above the...Ch. 2 - Space pirates kidnap an earthling and hold him on...Ch. 2 - Example 2.3: A jetliner touches down at 288 km/h....Ch. 2 - Prob. 42ECh. 2 - Prob. 43ECh. 2 - Prob. 44ECh. 2 - Example 2.5: A diver drops from a 9.21-m high...Ch. 2 - Prob. 46ECh. 2 - Prob. 47ECh. 2 - Prob. 48ECh. 2 - You allow 40 min to drive 25 mi to the airport,...Ch. 2 - Prob. 50PCh. 2 - You can run 9.0 m/s, 20% faster than your brother....Ch. 2 - Prob. 52PCh. 2 - An objects position is given by x = bt + ct3 where...Ch. 2 - An objects position as a function of time t is...Ch. 2 - In a 400-m drag race, two cars start at the same...Ch. 2 - Squaring Equation 2.7 gives an expression for v2....Ch. 2 - During the complicated sequence that landed the...Ch. 2 - The position of a car in a drag race is measured...Ch. 2 - A fireworks rocket explodes at a height of 82.0 m,...Ch. 2 - The muscles in a grasshoppers legs can propel the...Ch. 2 - On packed snow, computerized antilock brakes can...Ch. 2 - A particle leaves its initial position x0 at time...Ch. 2 - A hockey puck moving at 32 m/s slams through a...Ch. 2 - Prob. 64PCh. 2 - A jetliner touches down at 220 km/h and comes to a...Ch. 2 - A motorist suddenly notices a stalled car and...Ch. 2 - A racing car undergoing constant acceleration...Ch. 2 - The maximum braking acceleration of a car on a dry...Ch. 2 - After 35 min of running, at the 9-km point in a...Ch. 2 - Youre speeding at 85 km/h when you notice that...Ch. 2 - Airbags cushioned the Mars rover Spirits landing,...Ch. 2 - Calculate the speed with which cesium atoms must...Ch. 2 - A falling object travels one-fourth of its total...Ch. 2 - Youre on a NASA team engineering a probe to land...Ch. 2 - Youre atop a building of height h, and a friend is...Ch. 2 - A castles defenders throw rocks down on their...Ch. 2 - Two divers jump from a 3.00-m platform. One jumps...Ch. 2 - A balloon is rising at 10 m/s when its passenger...Ch. 2 - In 2014 the Philae spacecraft became the first...Ch. 2 - Youre at mission control for a rocket launch,...Ch. 2 - Youre an investigator for the National...Ch. 2 - Prob. 82PCh. 2 - Consider an object traversing a distance L, part...Ch. 2 - Prob. 84PCh. 2 - Ice skaters, ballet dancers, and basketball...Ch. 2 - Youre staring idly out your dorm window when you...Ch. 2 - A police radars effective range is 1.0 km, and...Ch. 2 - An object starts moving in a straight line from...Ch. 2 - Youre a consultant on a movie set, and the...Ch. 2 - (a) For the ball in Example 2.6, find its velocity...Ch. 2 - Your roommate is an aspiring novelist and asks...Ch. 2 - Prob. 92PCh. 2 - Derive Equation 2.10 by integrating Equation 2.7...Ch. 2 - An objects acceleration increases quadratically...Ch. 2 - An object’s velocity as a function of time is...Ch. 2 - An objects acceleration decreases exponentially...Ch. 2 - A ball is dropped from rest at a height li0 above...Ch. 2 - A wildlife biologist is studying the hunting...Ch. 2 - A wildlife biologist is studying the hunting...Ch. 2 - A wildlife biologist is studying the hunting...Ch. 2 - A wildlife biologist is studying the hunting...Ch. 2 - A wildlife biologist is studying the hunting...
Additional Science Textbook Solutions
Find more solutions based on key concepts
A physics major is cooking breakfast en she notices that the frictional force between her steel spatula and Tef...
University Physics Volume 1
One way an atom emits light (photons) occurs when an electron drops down from a high energy level (also referre...
Lecture- Tutorials for Introductory Astronomy
The total positive charge and total negative charge in a solid copper penny.
College Physics: A Strategic Approach (3rd Edition)
Choose the best answer to each of the following. Explain your reasoning. About how many galaxies are there in a...
The Cosmic Perspective Fundamentals (2nd Edition)
3. What is free-fall, and why does it make you weightless? Briefly describe why astronauts are weightless in th...
The Cosmic Perspective
Explain all answers clearly, with complete sentences and proper essay structure, if needed. An asterisk (*) des...
Cosmic Perspective Fundamentals
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
- You are driving along Lawrence Ave. at 60 km/h. You see the traffic light ahead is still green and decide to speed up to try to make it through the intersection before it turns red (poor decision!). Your car accelerates at 1.3 m/s?. You reach the light after accelerating for 4.3 seconds. What is your speed at the light in m/s? v, =v, +aAt A: Pictorial Representation Sketch showing events, describe events, coordinate system, label givens & unknowns with symbols, conversions B: Physics Representation Motion diagram, motion graphs, velocity vectors, events LLL. a +x t C: Word Representation Describe motion (no numbers),-assumptions, estimated result (no calculation) D: Mathematical Representation Describe physics of steps, complete equations, algebraically isolate, substitutions with units, final statement of prediction E: Evaluation Answer has reasonable size, direction and units? Why?arrow_forwardTwo ants pass each other one is moving along the negative x axis and one is moving at 45 degrees to the x axis. Ant 1 goes 0.032 and ant 2 goes 0.070 m/s. Ant going .070 m/s begins to accelerate as soon as the two pass each other. The acceleration is .001 m/s2. How far apart will the two ants be after 2 seconds?arrow_forwardCar A was traveling east at high speed when it collided at point O with car B , which was traveling north at 45 mi/h. Car C , which was traveling west at 60 mi/h, was 32 ft east and 10 ft north of point O at the time of the collision. Because the pavement was wet, the driver of car C could not prevent his car from sliding into the other two cars, and the three cars, stuck together, kept sliding until they hit the utility pole p. Knowing that the weights of cars A, B, and C are, respectively, 3000 lb, 2600 lb, and 2400 lb, and neglecting the forces exerted on the cars by the wet pavement, solve the problems indicated.Knowing that the coordinates of the utility pole are xp= 46 ft and yp = 59 ft, determine (a) the time elapsed from the first collision to the stop at P,(b) the speed of car A.arrow_forward
- As a science project, you drop a watermelon off the top of the Empire State Building, 320 m above the sidewalk. It so happens that Superman flies by at the instant you release the watermelon. Superman is headed straight down with a speed of 37.0 m/sm/s.How fast is the watermelon going when it passes Superman?arrow_forwardYou are walking down a straight path in a park and notice there is another person walking some distance ahead of you. The distance between the two of you remains the same, so you deduce that you are walking at the same speed of 1.17 m/s.1.17 m/s. Suddenly, you notice a wallet on the ground. You pick it up and realize it belongs to the person in front of you. To catch up, you start running at a speed of 2.85 m/s.2.85 m/s. It takes you 14.5 s14.5 s to catch up and deliver the lost wallet. How far ahead of you was this person when you started running?arrow_forwardA cat is sleeping on the floor in the middle of a 3.0 m wide room when a barking dog enters with a speed of 1.50 m/s. As the dog enters, the cat immediately accelerates at 0.85 m/s2 toward an open window on the opposite side of the room. The dog is a bit startled by the cat and begins to slow down at 0.10 m/s2 as soon as it enters the room. How far is the cat in front of the dog as it leaps through the window?arrow_forward
- A ball is moving towards you at a velocity of 15 m/s [E]. You kick it, and the ball leaves foot with a velocity of 13 m/s [W]. The ball was in contact with the your foot for 0.4 s. What was the magnitude of the acceleration of the puck, in m/s²? Use a kinematic approach.arrow_forwardYou are driving along Lawrence Ave. at 60 km/h. You see the traffic light ahead is still green and decide to speed up to try to make it through the intersection before it turns red (poor decision!). Your car accelerates at 1.3 m/s. You reach the light after accelerating for 4.3 seconds. What is your speed at the light in m/s? V =v, +aAt A: Pictorial Representation Sketch showing events, describe events, coordinate system, label givens & unknowns with symbols, conversions B: Physics Representation Motion diagram, motion graphs, velocity vectors, events a C: Word Representation Describe motion (no numbers),-assumptions, estimated result (no calculation) D: Mathematical Representation Describe physics of steps, complete equations, algebraically isolate, substitutions with units, final statement of prediction E: Evaluation Answer has reasonable size, direction and units? Why?arrow_forwardTwo cars are moving towards an intersection. One car is 150 meters north of the intersection and moving towards the intersection at 20 m/s, while the other is 180 meters west of the intersection and moving towards the intersection at 16 m/s. How rapidly are the cars approaching each other 4 seconds later?arrow_forward
- A girl is standing at the edge of a cliff 100. m above the ground. She reaches out over the edge of the cliff and throws a rock straight upward with a speed 8.00 m/s. a) How long does it take the rock to hit the ground? b) What is the speed of the rock the instant before it hits the ground?arrow_forwardA distance of 60 meters separates two jetskis at Virginia Beach. Starting at rest, the jetskis accelerate at a constant rate of 0.2 m/s2 towards each other.Starting at a midpoint between the two jetskis, a porpoise is seen swimming from one jetski to the other at a constant speed of 16 m/s. The porpoise continues swimming back and forth between the jetskis until they crash together.a) What is the total distance the porpoise travelled? b) what is the speed of the jetskis when they crash together?arrow_forwardI am driving at 35 mph on a foggy day when I see a car 5 miles ahead of me stopped in the road with its hazard lights on. I can accelerate my car at about -12 mph/s. How long do I have to decide if I will need to swerve to avoid hitting the car? Which is the correct equation to usearrow_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-Hill
Glencoe Physics: Principles and Problems, Student...
Physics
ISBN:9780078807213
Author:Paul W. Zitzewitz
Publisher:Glencoe/McGraw-Hill
Position/Velocity/Acceleration Part 1: Definitions; Author: Professor Dave explains;https://www.youtube.com/watch?v=4dCrkp8qgLU;License: Standard YouTube License, CC-BY