Section 1 Acceleration: Practice Problems
Chapter 3 Practice Problems, Review, and AssessmentSection 1 Acceleration: Practice Problems2. Use the v-t graph of the toy train in Figure 9 to answer these questions.a. When is the train’s speed constant?b. During which time interval is the train’s acceleration positive?c. When is the train’s acceleration most negative?SOLUTION:a. 5.0 to 15.0 sb. 0.0 to 5.0 sc. 15.0 to 20.0 sANSWER:a. 5.0 to 15.0 sb. 0.0 to 5.0 sc. 15.0 to 20.0 s3. Refer to Figure 9 to find the average acceleration of the train during the following time intervals.a. 0.0 s to 5.0 sb. 15.0 s to 20.0 sc. 0.0 s to 40.0 sSOLUTION:eSolutions Manual - Powered by CogneroPage 1
ANSWER:a. 5.0 to 15.0 sb. 0.0 to 5.0 sChapter3 Practicec. 15.0to 20.0 sProblems, Review, and Assessment3. Refer to Figure 9 to find the average acceleration of the train during the following time intervals.a. 0.0 s to 5.0 sb. 15.0 s to 20.0 sc. 0.0 s to 40.0 sSOLUTION:ANSWER:a.b.c.4. CHALLENGE Plot a v-t graph representing the following motion: An elevator starts at rest from the ground floor2of a three-story shopping mall. It accelerates upward for 2.0 s at a rate of 0.5 m/s , continues up at a constant2velocityof-1.0m/s for12.0 s, and then slows down with a constant downward acceleration of 0.25 m/s for 4.0 sPageas 2eSolutionsManualPoweredby Cogneroit reaches the third floor.SOLUTION:
ANSWER:a.b. 3 Practice Problems, Review, and AssessmentChapterc.4. CHALLENGE Plot a v-t graph representing the following motion: An elevator starts at rest from the ground floor2of a three-story shopping mall. It accelerates upward for 2.0 s at a rate of 0.5 m/s , continues up at a constant2velocity of 1.0 m/s for 12.0 s, and then slows down with a constant downward acceleration of 0.25 m/s for 4.0 s asit reaches the third floor.SOLUTION:ANSWER:5. A race car’s forward velocity increases from 4.0 m/s to 36 m/s over a 4.0-s time interval. What is its averageacceleration?SOLUTION:ANSWER:6. The race car in the previous problem slows from 36 m/s to 15 m/s over 3.0 s. What is its average acceleration?SOLUTION:ANSWER:eSolutions Manual - Powered by CogneroPage 38. A car is coasting backward downhill at a speed of 3.0 m/s when the driver gets the engine started. After 2.5 s, thecar is moving uphill at 4.5 m/s. If uphill is chosen as the positive direction, what is the car’s average acceleration?
ANSWER:Chapter3 Practice Problems, Review, and Assessment6. The race car in the previous problem slows from 36 m/s to 15 m/s over 3.0 s. What is its average acceleration?SOLUTION:ANSWER:8. A car is coasting backward downhill at a speed of 3.0 m/s when the driver gets the engine started. After 2.5 s, thecar is moving uphill at 4.5 m/s. If uphill is chosen as the positive direction, what is the car’s average acceleration?SOLUTION:ANSWER:Section 1 Acceleration: Review13. Velocity-Time Graph Sketch a velocity-time graph for a car that goes east at 25 m/s for 100 s, then west at 25 m/sfor another 100 s.SOLUTION:ANSWER:14. Average Velocity and Average Acceleration A canoeist paddles upstream at a velocity of 2.0 m/s for 4.0 s andthen floats downstream at 4.0 m/s for 4.0 s.a. What is the average velocity of the canoe during the 8.0-s time interval?b. What is the average acceleration of the canoe during the 8.0-s time interval?eSolutions Manual - Powered by CogneroSOLUTION:a. Choose a coordinate system with the positive direction upstream.Page 4
Chapter 3 Practice Problems, Review, and Assessment14. Average Velocity and Average Acceleration A canoeist paddles upstream at a velocity of 2.0 m/s for 4.0 s andthen floats downstream at 4.0 m/s for 4.0 s.a. What is the average velocity of the canoe during the 8.0-s time interval?b. What is the average acceleration of the canoe during the 8.0-s time interval?SOLUTION:a. Choose a coordinate system with the positive direction upstream.b.ANSWER:a. Choose a coordinate system with the positive direction upstream.b.Chapter AssessmentSection 1 Acceleration: Mastering Concepts54. Give an example of each of the following:a. an object that is slowing down, but has a positive accelerationb. an object that is speeding up but has a negative accelerationc. an object that is moving at a constant speed but has an accelerationSOLUTION:a. if forward is the positive direction, a car moving backward at decreasing speedb. in the same coordinate system, a car moving backward at increasing speedc. a car that is moving on a circular track at a constant speedANSWER:a. if forward is the positive direction, a car moving backward at decreasing speedb. inManualthe samecoordinateeSolutions- Poweredby Cognerosystem, a car moving backward at increasing speedc. a car that is moving on a circular track at a constant speedPage 5
ANSWER:a. Choose a coordinate system with the positive direction upstream.Chapter 3 Practice Problems, Review, and Assessmentb.Chapter AssessmentSection 1 Acceleration: Mastering Concepts54. Give an example of each of the following:a. an object that is slowing down, but has a positive accelerationb. an object that is speeding up but has a negative accelerationc. an object that is moving at a constant speed but has an accelerationSOLUTION:a. if forward is the positive direction, a car moving backward at decreasing speedb. in the same coordinate system, a car moving backward at increasing speedc. a car that is moving on a circular track at a constant speedANSWER:a. if forward is the positive direction, a car moving backward at decreasing speedb. in the same coordinate system, a car moving backward at increasing speedc. a car that is moving on a circular track at a constant speed56. If the velocity-time graph of an object moving on a straight path is a line parallel to the horizontal axis, what can youconclude about the object’s acceleration?SOLUTION:When the velocity-time graph is a line parallel to the horizontal axis, the acceleration is zero.ANSWER:When the velocity-time graph is a line parallel to the horizontal axis, the acceleration is zero.Chapter AssessmentSection 1 Acceleration: Mastering Problems57. Ranking Task Rank the following objects according to the magnitude of the acceleration, from least to greatest.Specifically indicate any ties. (Level 1)A. A falling acorn accelerates from 0.50 m/s to 10.3 m/s in 1.0 s.B. A car accelerates from 20 m/s to rest in 1.0 s.C. A centipede accelerates from 0.40 cm/s to 2.0 cm/s in 0.50 s.D. While being hit, a golf ball accelerates from rest to 4.3 m/s in 0.40 s.E. A jogger accelerates from 2.0 m/s to 1.0 m/s in 8.3 s.SOLUTION:From least to greatest magnitude of acceleration: C E A D B.A.B.C.eSolutions Manual - Powered by CogneroPage 6
ANSWER:When the velocity-time graph is a line parallel to the horizontal axis, the acceleration is zero.Chapter 3 Practice Problems, Review, and AssessmentChapter AssessmentSection 1 Acceleration: Mastering Problems57. Ranking Task Rank the following objects according to the magnitude of the acceleration, from least to greatest.Specifically indicate any ties. (Level 1)A. A falling acorn accelerates from 0.50 m/s to 10.3 m/s in 1.0 s.B. A car accelerates from 20 m/s to rest in 1.0 s.C. A centipede accelerates from 0.40 cm/s to 2.0 cm/s in 0.50 s.D. While being hit, a golf ball accelerates from rest to 4.3 m/s in 0.40 s.E. A jogger accelerates from 2.0 m/s to 1.0 m/s in 8.3 s.SOLUTION:From least to greatest magnitude of acceleration: C E A D B.A.B.C.D.E.ANSWER:From least to greatest magnitude of acceleration: C E A D B.59. The graph in Figure 27 describes the motion of an object moving east along a straight path. Find the acceleration ofthe object at each of these times: (Level 1)eSolutions Manual - Powered by Cogneroa. during the first 5.0 min of travelb. between 5.0 min and 10.0 minPage 7
ANSWER:From least to greatest magnitude of acceleration: C E A D B.Chapter 3 Practice Problems, Review, and Assessment59. The graph in Figure 27 describes the motion of an object moving east along a straight path. Find the acceleration ofthe object at each of these times: (Level 1)a. during the first 5.0 min of travelb. between 5.0 min and 10.0 minc. between 10.0 min and 15.0 mind. between 20.0 min and 25.0 minSOLUTION:a. Let east be the positive direction.b.c.d.eSolutions Manual - Powered by CogneroANSWER:Page 8
Chapter 3 Practice Problems, Review, and Assessmentd.ANSWER:a. Let east be the positive direction. 6.0m/min2 eastb.c.d. 0.0m/min2 2.0m/min2 west 4.0m/min2 westChapter AssessmentSection 2 Motion with Constant Acceleration: Mastering Problems68. Refer to Figure 29 to find the magnitude of the displacement during the following time intervals. Round answers tothe nearest meter.a. t 5.0 min and t 10.0 minb. t 10.0 min and t 15.0 minc. t 25.0 min and t 30.0 mind. t 0.0 min and t 25.0 minSOLUTION:a.b. Area (15 m/min)(5 min) 75 mc.eSolutions Manual - Powered by Cognerod.Page 9
c.d. 2.0m/min west 4.0m/min2 westChapter 3 Practice Problems, Review, and AssessmentChapter AssessmentSection 2 Motion with Constant Acceleration: Mastering Problems68. Refer to Figure 29 to find the magnitude of the displacement during the following time intervals. Round answers tothe nearest meter.a. t 5.0 min and t 10.0 minb. t 10.0 min and t 15.0 minc. t 25.0 min and t 30.0 mind. t 0.0 min and t 25.0 minSOLUTION:a.b. Area (15 m/min)(5 min) 75 mc.d.ANSWER:a. 88 mb. 75 mc. 13 md. 288 mChapter Assessment: Applying ConceptseSolutions Manual - Powered by Cognero78. Explain how you would walk to produce each of the position-time graphs in Figure 30.Page 10
a. 88 mb. 75 mc. 13 mChapter3 PracticeProblems, Review, and Assessmentd. 288mChapter Assessment: Applying Concepts78. Explain how you would walk to produce each of the position-time graphs in Figure 30.SOLUTION:(1) Walk in the positive direction at a constant speed. (2) Walk in the positive direction at an increasingspeed for a short time; keep walking at a moderate speed for twice that amount of time; slow down overa short time and stop; remain stopped; and turn around and repeat the procedure until the originalposition is reached.ANSWER:(1) Walk in the positive direction at a constant speed. (2) Walk in the positive direction at an increasingspeed for a short time; keep walking at a moderate speed for twice that amount of time; slow down overa short time and stop; remain stopped; and turn around and repeat the procedure until the originalposition is reached.eSolutions Manual - Powered by CogneroPage 11
Section 1 Acceleration: Practice Problems Use the v-t graph of the toy train in )LJXUH to answer these questions. a. When is the train ¶s speed constant? b. During which time interval is the train ¶s acceleration positive? c. When is the train ¶s acceleration most negative? 62/87,21 D WR V b. 0.0 to 5.0 s c. 15.0 to 20.0 s 16:(5
Centripetal Acceleration" The acceleration of an object moving in a circular path and at constant speed is due to a change in direction." An acceleration of this nature is called a centripetal acceleration. CENTRIPETAL ACCELERATION ac vt 2 r centripetal acceleration (tangential speed)2 radius of circular path Section 1 Circular Motion
3.1 Which of the following statements correctly defines acceleration? Question 1 A. Acceleration is the rate of change of displacement of an object. B. Acceleration is the rate of change of velocity of an object. C. Acceleration is the amount of distance covered in unit time. D. Acceleration is the rate of change of speed of an object. Section .
(b) The centripetal acceleration is half as large because centripetal acceleration depends on the inverse of the radius: 1 2 a c v2 2r. (c) The centripetal acceleration is four times as great because centripetal acceleration depends on the square of the speed: 4a c (2v)2 r. 2.
Two common problems 1. Acceleration and velocity are always in the same direction a. No, as an object is thrown upward, velocity is y, acceleration is –y 2. Acceleration is zero at the highest point. a. No, at the highest point, the velocity is zero, but acceleration is always - 9.80m/s2 b. The object changes velocity, it must have an .
Chapter: Motion, Acceleration, and Forces Table of Contents Section 3: Motion and Forces . also are accelerated. Acceleration This acceleration makes them feel as if a . Sometimes it is obvious that a force has been applied. 3 Motion and Forces But other forces arenÕt as noticeable. Changing Motion
1 Problems: What is Linear Algebra 3 2 Problems: Gaussian Elimination 7 3 Problems: Elementary Row Operations 12 4 Problems: Solution Sets for Systems of Linear Equations 15 5 Problems: Vectors in Space, n-Vectors 20 6 Problems: Vector Spaces 23 7 Problems: Linear Transformations 28 8 Problems: Matrices 31 9 Problems: Properties of Matrices 37
max r 1 s 2g(m 2r 2 m 1r 1) m 1r2 1 m 2r22 3:05 r 2 9:81(58 0:15 0:130 3:05) 0:130 3:052 58 0:152 24:55 m s b) The overall acceleration is changing direction throughout the motion. Vector acceleration is thus not constant. c) and d) Neither tangential acceleration nor angular acceleration are constant. First of all, the two are .
group of employees at his work. Derogatory homophobic : comments have been posted on the staff noticeboard about him by people from this group. Steve was recently physically pushed to the floor by one member of the group but is too scared to take action. Steve is not gay but heterosexual; furthermore the group know he isn’t gay. This is harassment related to sexual orientation. Harassment at .
