Essential University Physics (3rd Edition)
3rd Edition
ISBN: 9780134202709
Author: Richard Wolfson
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 2, Problem 49P
In a drag race, the position of a car as a function of time is given by x = bt2, with b = 2.000 m/s2. In an attempt to determine the car’s velocity midway down a 400-m track, two observers stand at the 180-m and 220-m marks and note when the car passes, (a) What value do the two observers compute for the car’s velocity over this 40-m stretch? Give your answer to four significant figures. (b) By what percentage does this observed value differ from the instantaneous value at x = 200 m?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
You encounter a moving walkway that is 81 m long and has a speed of 2.1 m/s relative to the ground.
How long would it take you to cover the 81 m length of the walkway if, once you get on the walkway, you immediately turn around and start walking in the opposite direction with a speed of 1.6 m/s relative to the walkway?
Express your answer using one significant figure.
In the vertical jump, an athlete starts from a crouch and jumps upward to reach as high as possible. Even the best athletes spend little more than 1.00 s in the air (their "hang time"). Treat the athlete as a particle and let ymax be his maximum height above the floor.To explain why he seems to hang in the air, calculate the ratio of the time he is above ymax/2 (moving up from ymax/2 to ymax and then moving down to ymax/2) to the time it takes him to go from the floor to that height. You may ignore air resistance.
A particle moves according to a law of motion
s = f(t), t ≥ 0,
where t is measured in seconds and s in feet.
f(t) = t3 − 15t2 + 72t
(a) Find the velocity at time t.
v(t) =
(b) What is the velocity after 5 s?
v(5) = ft/s
(c) When is the particle at rest?
t = s (smaller value)
t = s (larger value)
(d) When is the particle moving in the positive direction? (Enter your answer in interval notation.)
t
(e) Find the total distance traveled during the first 8 s.ft(f) Find the acceleration at time t.
a(t) =
Find the acceleration after 5 s.
a(5) = ft/s2
(g) Graph the position, velocity, and acceleration functions for the first 8 s.
(h) When, for
0 ≤ t < ∞,
is the particle speeding up? (Enter your answer in interval notation.)
When, for
0 ≤ t < ∞,
is it slowing down? (Enter your answer in interval notation.)
Chapter 2 Solutions
Essential University Physics (3rd Edition)
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 - Starting from rest, an object undergoes...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 - The standard 26-mile, 385-yard marathon dates to...Ch. 2 - Starting front home, you bicycle 24 km north in...Ch. 2 - The Voyager 1 spacecraft is expected to continue...Ch. 2 - In 2008, Australian Emma Snowsill set an...Ch. 2 - Taking Earths orbit to be a circle of radius 1.5 ...Ch. 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 - A giant eruption on the Sun propels solar material...Ch. 2 - Starting from rest, a subway train first...Ch. 2 - A space shuttles main engines cut off 8.5 min...Ch. 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. 29ECh. 2 - An X-ray tube gives electrons constant...Ch. 2 - A rocket rises with constant acceleration to an...Ch. 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 - You drop a rock into a deep well and 4.4 s later...Ch. 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 - You allow 40 min to drive 25 mi to the airport,...Ch. 2 - A base runner can get from first to second base in...Ch. 2 - You can run 9.0 m/s, 20% faster than your brother....Ch. 2 - A jetliner leaves San Francisco for New York, 4600...Ch. 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 drag race, the position of a car as a...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 - Amtraks 20th-Century Limited is en route from...Ch. 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 - Landing on the Moon, a spacecraft fires its...Ch. 2 - Youre at mission control for a rocket launch,...Ch. 2 - Youre an investigator for the National...Ch. 2 - You toss a book into your dorm room, just clearing...Ch. 2 - Consider an object traversing a distance L, part...Ch. 2 - A particles position as a function of time is...Ch. 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 - You and your roommate plot to drop water balloons...Ch. 2 - Derive Equation 2.10 by integrating Equation 2.7...Ch. 2 - An objects acceleration increases quadratically...Ch. 2 - An objects acceleration is given by the expression...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
3. What is free-fall, and why does it make you weightless? Briefly describe why astronauts are weightless in th...
The Cosmic Perspective
The self-inductance of a coil is zero if there is no current passing through the windings. True or false?
University Physics Volume 2
The pV-diagram of the Carnot cycle.
Sears And Zemansky's University Physics With Modern Physics
Biologists measure the total current due to potassium ions moving through the membrane of a rock crab neuron ce...
Essential University Physics: Volume 2 (3rd Edition)
3. What is free-fall, and why does it make you weightless? Briefly describe why astronauts are weightless in th...
The Cosmic Perspective (8th Edition)
Consider the two experiments described above. When the momentum of an object or system of objects did not chang...
Tutorials in Introductory Physics
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
- A rocket ship has a position given by x(t)=bt2 meters. In order for it to reach a velocity of 5,000 m/s in 40,000 meters, what must be the value of b?arrow_forwardTwo runners start simultaneously from the same point on a circular 200-m track and run in opposite directions. One runs at a constant speed of 6.20 m/s, and the other runs at a constant speed of 5.50 m/s. When they first meet, (a) for how long a time will they have been running, and (b) how far will each one have run along the track?arrow_forwardOn a two-lane road, car A is travelling with a speed of 72 km/h. Two cars B and C approach car A in opposite directions with a speed of 108 km/h each. At a certain instant, when the distance AB is equal to AC, both being 2 km, B decides to overtake A before C does. What minimum acceleration of car B is required to avoid an accident ?arrow_forward
- The sport with the fastest moving ball is jai alai, where measured speeds have reached 303 km/h. If a professional jai alai player faces a ball at that speed and involuntarily blinks, he blacks out the scene for 100 ms. How far does the ball move during the blackout?arrow_forwardMost important in an investigation of an airplane crash by the U.S. National Transportation Safety Board is the data stored on the airplane’s flight-data recorder, commonly called the “black box” in spite of its orange coloring and reflective tape.The recorder is engineered to withstand a crash with an average deceleration of magnitude 3450 g during a time interval of 6.49 ms. In such a crash, if the recorder and airplane have zero speed at the end of that time interval, what is their speed at the beginning of the interval?arrow_forwardTraveling with an initial speed of 70 kph, a car accelerates at 6000 km/hr2 along a straight road. How long will ittake to reach a speed of 120 kph? Also, through what distance does the car travel during this time?arrow_forward
- An unidentified flying object (UFO) is observed to travel a total distance of 19000 m, starting and ending at rest, over a duration of 4.23 s. Assuming the UFO accelerated at a constant rate to the midpoint of its journey and then decelerated at a constant rate the rest of the way, what was the magnitude of its acceleration? Express your answer in g s , where 1 g = 9.81 m/s^2.arrow_forwardA classic physics problem states that if a projectile is shot vertically up into the air with an initial velocity of 146 feet per second from an initial height of 89 feet off the ground, then the height of the projectile, h, in feet, t seconds after it's shot is given by the equation: h=−16t2+146t+89h=-16t2+146t+89 Find the two points in time when the object is 126 feet above the ground (to one decimal places). Answer: The object is 126 feet off the ground at the following times: (Enter your two answers separated by a comma. Round to ONE decimal places.)arrow_forwardA daredevil jumps off a tall building. He falls freely for several secondsbefore releasing his parachute. His height (h) in meters, ? seconds afterjumping can be modeled by h = −4.9?2 + ? + 360 before he releases hisparachute and h = −4? + 142 after he released his parachute. How longafter jump did he release his parachute?arrow_forward
- After a ball rolls off the edge of a horizontal table at time t = 0, its velocity as a function of time is given by:v = 1.2 i - 9.8t jwhere v is in meters per second and t is in seconds. The ball’s displacement away from the edge of the table, during the time interval of 0.380 s for which the ball is in flight, is given by:Δ⃗r=∫00.380s⃗vdtTo perform the integral, you can use the calculus theorem:∫[A+Bf(x)]dx=∫Adx+B∫f(x)dx You can think of the units and unit vectors as constants, represented by A and B. Perform the integration to calculate the displacement of the ball from the edge of the table at 0.380 sarrow_forwardThe following table gives the position s1t2 of an object moving along a line at time t. Determine the average velocities over the time intervals 31, 1.014, 31, 1.0014, and 31, 1.00014. Then make a conjecture about the value of the instantaneous velocity at t = 1.arrow_forwardYou are exploring a planet and drop a small rock from the edge of a cliff. In coordinates where the +y direction is downward and neglecting air resistance, the vertical displacement of an object released from rest is given by y − y0 = 1/2gplanett2, where gplanet is the acceleration due to gravity on the planet. You measure t in seconds for several values of y − y0 in meters and plot your data with t2 on the vertical axis and y − y0 on the horizontal axis. Your data is fit closely by a straight line that has slope 0.300 s2/m. Based on your data, what is the value of gplanet?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning
University Physics (14th Edition)PhysicsISBN:9780133969290Author:Hugh D. Young, Roger A. FreedmanPublisher:PEARSON
Introduction To Quantum MechanicsPhysicsISBN:9781107189638Author:Griffiths, David J., Schroeter, Darrell F.Publisher:Cambridge University Press
Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Lecture- Tutorials for Introductory AstronomyPhysicsISBN:9780321820464Author:Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina BrissendenPublisher:Addison-Wesley
College Physics: A Strategic Approach (4th Editio...PhysicsISBN:9780134609034Author:Randall D. Knight (Professor Emeritus), Brian Jones, Stuart FieldPublisher:PEARSON
College Physics
Physics
ISBN:9781305952300
Author:Raymond A. Serway, Chris Vuille
Publisher:Cengage Learning
University Physics (14th Edition)
Physics
ISBN:9780133969290
Author:Hugh D. Young, Roger A. Freedman
Publisher:PEARSON
Introduction To Quantum Mechanics
Physics
ISBN:9781107189638
Author:Griffiths, David J., Schroeter, Darrell F.
Publisher:Cambridge University Press
Physics for Scientists and Engineers
Physics
ISBN:9781337553278
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Lecture- Tutorials for Introductory Astronomy
Physics
ISBN:9780321820464
Author:Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina Brissenden
Publisher:Addison-Wesley
College Physics: A Strategic Approach (4th Editio...
Physics
ISBN:9780134609034
Author:Randall D. Knight (Professor Emeritus), Brian Jones, Stuart Field
Publisher:PEARSON
Relative Velocity - Basic Introduction; Author: The Organic Chemistry Tutor;https://www.youtube.com/watch?v=_39hCnqbNXM;License: Standard YouTube License, CC-BY