Concept explainers
* The motion of a person as seen by another person is described by the equation
(a) Represent this motion with a motion diagram and position-, velocity-, and acceleration-versus-time graphs. (b) Say everything you can about this motion and describe what happens to the person when his speed becomes zero.
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
College Physics: Explore And Apply, Volume 2 (2nd Edition)
Additional Science Textbook Solutions
College Physics
Conceptual Physics (12th Edition)
College Physics: A Strategic Approach (4th Edition)
Essential University Physics (3rd Edition)
College Physics: A Strategic Approach (3rd Edition)
Physics: Principles with Applications
- Draw motion diagrams for (a) an object moving to the right at constant speed, (b) an object moving to the right and speeding up at a constant rate, (c) an object moving to the right and slowing down at a constant rate, (d) an object moving to the left and speeding up at a constant rate, and (e) an object moving to the left and slowing down at a constant rate. (f) How would your drawings change if the changes in speed were not uniform, that is, if the speed were not changing at a constant rate?arrow_forwardA student drives a moped along a straight road as described by the velocitytime graph in Figure P2.32. Sketch this graph in the middle of a sheet of graph paper. (a) Directly above your graph, sketch a graph of the position versus time, aligning the time coordinates of the two graphs. (b) Sketch a graph of the acceleration versus time directly below the velocitytime graph, again aligning the time coordinates. On each graph, show the numerical values of x and ax for all points of inflection. (c) What is the acceleration at t = 6.00 s? (d) Find the position (relative to the starting point) at t = 6.00 s. (e) What is the mopeds final position at t = 9.00 s? Figure P2.32arrow_forwardA speedboat increases its speed uniformly from vi = 20.0 m/s to Vf = 30.0 m/s in a distance of 2.00 102 m. (a) Draw a coordinate system for this situation and label the relevant quantities, including vectors, (b) For the given information, what single equation is most appropriate for finding the acceleration? (c) Solve the equation selected in part (b) symbolically for the boats acceleration in terms of vf, vi, and x. (d) Substitute given values, obtaining that acceleration, (e) Find the time it takes the boat to travel the given distance.arrow_forward
- A glider on an air track carries a flag of length through a stationary photogate, which measures the time interval td during which the flag blocks a beam of infrared light passing across the photogate. The ratio vd = /td is the average velocity of the glider over this part of its motion. Suppose the glider moves with constant acceleration, (a) Is vd necessarily equal to the instantaneous velocity of the glider when it is halfway through the photogate in space? Explain. (b) Is vd equal to the instantaneous velocity of the glider when it is halfway through the photogate in time? Explain.arrow_forwardA cyclist rides 8.0 km east for 20 minutes, then he turns and heads west for 8 minutes and 3.2 km. Finally, he rides east for 16 km, which takes 40 minutes. (a) What is the final displacement of the cyclist? (b) What is his average velocity?arrow_forwardAn object that moves in one dimension has the velocity-versus-time graph shown in Figure P2.52. At time t = 0, the object has position x = 0. a. At time t = 5 s. is the acceleration of the object positive, negative, or zero? Explain. b. At time t = 8 s, is the object speeding up, showing down, or moving with constant speed? Explain. c. Write an expression for the position of the object as a function of time. Explain how you use the graph to obtain your answer. d. Use your expression from part (c) to determine the time (if any) at which the object reaches its maximum position. Check your results by examining the graph. Hint: To get started with finding the maximum of a function, take the derivative and set it equal to zero.arrow_forward
- A student drives a moped along a straight road as described by the velocity-versus-time graph in Figure P2.12. Sketch this graph in the middle of a sheet of graph paper. (a) Directly above your graph, sketch a graph of the position versus time, aligning the time coordinates of the two graphs. (b) Sketch a graph of the acceleration versus time directly below the velocity-versus-time graph, again aligning the time coordinates. On each graph, show the numerical values of x and ax for all points of inflection. (c) What is the acceleration at t = 6.00 s? (d) Find the position (relative to the starting point) at t = 6.00 s. (e) What is the mopeds final position at t = 9.00 s? Figure P2.12arrow_forwardThe Acela is an electric train on the WashingtonNew YorkBoston run, carrying passengers at 170 mi/h. A velocitytime graph for the Acela is shown in Figure P2.46. (a) Describe the trains motion in each successive time interval. (b) Find the trains peak positive acceleration in the motion graphed. (c) Find the trains displacement in miles between t = 0 and t = 200 s. Figure P2.46 Velocity versus time graph for the Acela.arrow_forwardStanding at the base of one of the cliffs of Mt. Arapiles in Victoria, Australia, a hiker hears a rock break loose from a height of 105 m. He can't see the rock right away but then does, 1.50 s later. (a) How far above the hiker is the rock when he can see it? (b) How much time does he have to move before the rock hits his head?arrow_forward
- Consider the following combinations of signs and values for the velocity and acceleration of a particle with respect to a one-dimensional x-axis: Velocity Acceleration a. Positive Positive b. Positive Negative c. Positive Zero d. Negative Positive e. Negative Negative f. Negative Zero g. Zero Positive h. Zero Negative Describe what the particle is doing in each case and give a real-life example for an automobile on an east-west one-dimensional axis, with east considered the positive direction.arrow_forwardPROBLEM A race car starting from rest accelerates at a constant rate of 5.00 m/s2, (a) What is the velocity of the car after it has traveled 1.00 102 ft? (b) How much time has elapsed? (c) Calculate the average velocity two different ways. STRATEGY Weve read the problem, drawn the diagram in Figure 2.16, and chosen a coordinate system (steps 1 and 2). We'd like to find the velocity v after a certain known displacement x. The acceleration a is also known, as is the initial velocity v0 (step 3, labeling, is complete), so the third equation in Table 2.4 looks most useful for solving part (a). Given the velocity, the first equation in Table 2.4 can then be used to find the time in part (b). Part (c) requires substitution into Equations 2.2 and 2.7, respectively. Figure 2.16 (Example 2.4) SOLUTION (a) Convert units of x to SI, using the information in the inside front cover. Write the kinematics equation for v2 (step 4): Solve for v, taking the positive square root because the car moves to the right (step 5): Substitute v0 = 0, a = 5.00 m/s2, and x = 30.5 m: 1.00 102ft = (1.00 102 ft) v2 = v02 + 2a x v = v02+2ax v = v02+2ax = (0)2+2(5.00m/s2)(30.5m)= 17.5 m/s (b) Find the trooper's speed at that time. Substitute the time into the troopers velocity equation: vtrooper = v0 + atrooper t = 0 + (3.00m/s2)(16.9s) = 50.7 m/s Solve Example 2.5, Car Chase, by a graphical method. On the same graph, plot position versus time for the car and the trooper. From the intersection of the two curves, read the time at which the trooper overtakes the car.arrow_forwardA speedboat travels in a straight line and increases in speed uniformly from vi = 20.0 m/s to vf = 30.0 m/s in a displacement x of 200 m. We wish to find the time interval required for the boat to move through this displacement. (a) Draw a coordinate system for this situation. (b) What analysis model is most appropriate for describing this situation? (c) From the analysis model, what equation is most appropriate for finding the acceleration of the speedboat? (d) Solve the equation selected in part (c) symbolically for the boats acceleration in terms of vi, vf, and x. (e) Substitute numerical values to obtain the acceleration numerically. (f) Find the time interval mentioned above.arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningUniversity Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice University