Concept explainers
You are driving toward a traffic signal when it turns yellow. Your speed is the legal speed limit of v0 = 55 km/h; your best deceleration rate has the magnitude a = 5.18 m/s2. Your best reaction time to begin braking is T = 0.75 s. To avoid having the front of your car enter the intersection after the light turns red, should you brake to a stop or continue to move at 55 km/h if the distance to the intersection and the duration of the yellow light are (a) 40 m and 2.8 s, and (b) 32 m and 1.8 s? Give an answer of brake, continue, either (if either strategy works), or neither (if neither strategy works and the yellow duration is inappropriate).
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
Fundamentals of Physics, Volume 1, Chapter 1-20
Additional Science Textbook Solutions
Glencoe Physical Science 2012 Student Edition (Glencoe Science) (McGraw-Hill Education)
Glencoe Physics: Principles and Problems, Student Edition
University Physics with Modern Physics (14th Edition)
Essential University Physics (3rd Edition)
EBK FUNDAMENTALS OF THERMODYNAMICS, ENH
Conceptual Physics: The High School Physics Program
- An ambulance driver is rushing a patient to the hospital. While traveling at 71.1 km/h, she notices the traffic light at the upcoming intersection has turned yellow. To reach the intersection before the light turns red, she must travel 52 m in 2.17 seconds. What is the magnitude of the minimum acceleration, in m/s2, required to reach the intersection before the light turns red?arrow_forwardThe driver of a car is initially moving at a constant speed of 70.4 km/h when a traffic light turns red. If a 0.520 s reaction time is required before the brakes can be applied, what is the distance in meters traveled by the car before it begins to slow down?arrow_forwardYou are driving your car, and the traffic light ahead turns red. You apply the brakes for 2.56 s, and the velocity of the car decreases to +4.84 m/s. The car’s deceleration has a magnitude of 3.67 m/s2 during this time. What is the car’s displacement?arrow_forward
- A chauffeur heads south with a steady speed of v₁ = 20.0 m/s for t₁ = 3.00 min, then makes a right turn and travels at V₂ = 25.0 m/s for t₂ = 2.40 min, and then drives northwest at v3 = 30.0 m/s for t3 = 1.00 min. For this 6.40-min trip, calculate the following. Assume +x is in the eastward direction. (a) total vector displacement (Enter the magnitude in m and the direction in degrees south of west.) magnitude direction (b) average speed (in m/s) m/s m • south of west (c) average velocity (Enter the magnitude in m/s and the direction in degrees south of west.) magnitude m/s direction ° south of westarrow_forwardA chauffeur heads south with a steady speed of v₁ = 20.0 m/s for t₁ = 3.00 min, then makes a right turn and travels at v₂ = 25.0 m/s for t₂ = 2.40 min, and then drives northwest at v3 = 30.0 m/s for t3 = 1.00 min. For this 6.40-min trip, calculate the following. Assume +x is in the eastward direction. (a) total vector displacement (Enter the magnitude in m and the direction in degrees south of west.) m magnitude direction o south of west (b) average speed (in m/s) m/s (c) average velocity (Enter the magnitude in m/s and the direction in degrees south of west.) magnitude m/sarrow_forwardA car is driving north with an initial speed v0. We will describe this in terms of a coordinate system with positive y-axis pointing north and positive x-axis pointing east. At t=0 the driver sees a red-light and begins to slow down with an acceleration a(t)=−At (where A is a positive constant) which brings the car to rest just as it reaches the red-light. The driver then immediately begins to accelerate east at a constant rate with a(t)=B .a) Using the coordinate system specified, write down the initial velocity vector v(0) . Hint: Do not overthink this part. You should not be integrating anything just yet, we are simply asking you to write down a vector describing the initial velocity (north at speed v0).b) Determine the amount of time that elapses between the time when the car starts to slow down and when it comes to rest at the stoplight. You should express your answer in terms of v0, A and B. Hint: You may not need all of these quantities.c) Now determine the total amount of time…arrow_forward
- A student begins at rest and then walks north at a speed of v1 = 0.55 m/s. The student then turns south and walks at a speed of v2 = 0.53 m/s. Take north to be the positive direction. If the student travels in the stated directions for 30.0 seconds at speed v1 and for 20.0 seconds at speed v2, what is the net displacement, in meters, during the trip? If it takes the student 5.0 s to reach the speed v1 from rest, what is the magnitude of the student’s average acceleration, in meters per second squared, during that time?arrow_forwardthe cat is being chased by a dog; they are running at 6m/s when they encounter a wall. The cat bounces off the wall and runs at 4m/s in the opposite direction, The cat is in contact with wall for only 0.05 seconds. What is the magnitude of the average acceleration of Steve while in contact with the wall?arrow_forwardA driver is traveling 18.0 m/s when she sees a red light ahead. Her car is capable of decelerating at a rate of 3.65m / (s ^ 2) If it takes her 0.380 s to get the brakes on and she is 24.0 m from the intersection when she sees the light, will she be able to stop in time? How far from the beginning of the intersection will she be, and in which direction?arrow_forward
- A bus bound to San Carlos City is moving up a steep hill in DSB at 30m/s when suddenly the engine stopped. The driver hits the brakes, but they don't work either. The bus starts to accelerate at -3m/s2. How far does it move forward before it starts sliding back down the hill?arrow_forwardA chauffeur heads south with a steady speed of v₁ = 22.0 m/s for t₁ = 3.00 min, then makes a right turn and travels at v₂ = 25.0 m/s for t₂ = 2.00 min, and then drives northwest at V3 = 30.0 m/s for t3 = 1.00 min. For this 6.00-min trip, calculate the following. Assume +x is in the eastward direction. (a) total vector displacement (Enter the magnitude in m and the direction in degrees south of west.) magnitude direction (b) average speed (in m/s) m/s m o south of west (c) average velocity (Enter the magnitude in m/s and the direction in degrees south of west.) m/s ° south of west magnitude directionarrow_forwardOn a one lane road, a person driving a car at v1 = 54 mi/h suddenly notices a truck 0.65 mi in front of him. That truck is moving in the same direction at v2 = 35 mi/h. In order to avoid a collision, the person has to reduce the speed of his car tov2 during time interval Δt. The smallest magnitude of acceleration required for the car to avoid a collision is a. During this problem, assume the direction of motion of the car is the positive direction. Refer to the figure. The expression, in terms of defined quantities, for the distance, Δx2, traveled by the truck during the time interval Δt is deltax2= v2 times delta t. Part (b) Enter an expression for the distance, Δx1, traveled by the car in terms of v1, v2 and a. Part (c) Enter an expression for the acceleration of the car, a, in terms of v1, v2, and Δt. (d) enter an expression for delta x1 in terms of delta x2 and d when the drive just barely avoids collision.arrow_forward
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningUniversity Physics (14th Edition)PhysicsISBN:9780133969290Author:Hugh D. Young, Roger A. FreedmanPublisher:PEARSONIntroduction 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 LearningLecture- Tutorials for Introductory AstronomyPhysicsISBN:9780321820464Author:Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina BrissendenPublisher:Addison-WesleyCollege Physics: A Strategic Approach (4th Editio...PhysicsISBN:9780134609034Author:Randall D. Knight (Professor Emeritus), Brian Jones, Stuart FieldPublisher:PEARSON