Name: _______________________ Mr. Kepple Chapter 2: Questions 1D Kinematics – HW#1 Date: ___________ Period: _____ 1. The figure shows four paths along which objects move from a starting point to a final point, all in the same time interval. The paths pass over a grid of equally spaced straight lines. (a) Rank the paths according to the average velocity of the objects, greatest first. Justify your ranking. All tie. The objects all have the same displacement in the same time interval, therefore they all have the same average velocity. (b) Rank the paths according to the average speed of the objects, greatest first. Justify your ranking. 4, 1 and 2, then 3. Since all of the objects moved over an equal time interval, the object that travels the greatest distance will have the greatest average speed. 2. The figure to the right is a graph of a particle’s position along an axis versus time. (a) Indicate below whether the sign of the particle’s position at is positive, negative, or zero. ___ Positive X Negative ___ Zero ___ Justify your answer: At 𝑡 the graph shows the position to be negative (below the horizontal axis). (b) Indicate below whether the particle’s velocity is positive, negative, or zero, at… i. s X Positive ___ ___ Zero ii. ___ Negative Justify your answer: The slope of a line tangent to the curve at this point is positive. s ___ Positive X Zero ___ iii. ___ Negative ___ Positive ___ Zero Justify your answer: X Negative ___ Justify your answer: The slope of a line tangent to the curve at this point is zero. (c) How many times does the particle go through the point s The slope of a line tangent to the curve at this point is negative. ? Justify your answer. The position 𝑥 is indicated on the graph by the horizontal axis. We can see that the curve crosses the horizontal axis twice: once at 𝑡 s and again at 𝑡 s. 3. The figure gives the velocity of a particle moving on an axis. (a) Indicate below whether the initial direction of travel is east, west, or if the particle is at rest. ___ East X West ___ ___ Rest Justify your answer: The initial direction of travel is indicated by the sign of the velocity at 𝑡 which is negative (west). (a) Indicate below whether the final direction of travel is east, west, or if the particle is at rest. (c) Indicate below whether the particle is ever at rest. X East ___ X Yes ___ ___ West ___ Rest ___ No Justify your answer: Justify your answer: The final direction of travel is indicated by the sign of the velocity at end of the curve which is positive (east). The velocity is zero on the horizontal axis and the object crosses the horizontal axis once. (d) Indicate whether the acceleration is positive, negative, or zero. (e) Indicate whether the acceleration is constant or varying. X Positive ___ ___ X Constant ___ Varying ___ Negative ___ Zero Justify your answer: Justify your answer: The acceleration of the object is indicated by the slope of the curve which is positive. The velocity curve is linear which indicates that the acceleration is constant. 4. The figure gives the velocity of a particle moving along an axis. (a) Indicate below whether the direction of travel at time east, west, or if the particle is at rest. ___ X East ___ West is ___ Rest Justify your answer: The direction of travel is indicated by the sign of the velocity at 𝑡 which is positive (east). (d) Indicate below whether the direction of travel at point 4 is east, west, or at rest. ___ East ___ X West ___ Rest Justify your answer: The direction of travel is indicated by the sign of velocity which is negative at 𝑡 4 s. (e) Rank the six points according to the magnitude of the acceleration, greatest first. 2 and 6 tie, then 3 and 5 tie, then 1 and 4 tie. The acceleration is found from the slope of the tangent to the curve, therefore the points with the greatest acceleration have the greatest slope. Name: _______________________ Mr. Kepple Motion Graphs – Part 1 1D Kinematics – HW#2 𝑣 Date: ___________ Period: _____ +𝑣 −𝑣 REST rest 𝑡 UM −𝑎 UM +𝑎 UM 1. The plot above shows the velocity vs. time of a particle. Indicate the interval over which the particle experiences the specified motion and then label that interval on the graph. When is the particle… (a) traveling in the positive direction? Label it! (b) traveling in the negative direction? Label it! (c) at rest? Label it! A to C C to F C and F to G (d) undergoing positive acceleration? Label it! (e) undergoing negative acceleration? Label it! (f) undergoing uniform motion? Label it! E to F B to D A to B, D to E, and F to G (g) speeding up? Label it! C to D (h) slowing down? Label it! B to C and E to F 𝑣 𝑡 2. Which point or points on the graph – if any – show instants at which there was… (a) Uniform motion in the positive direction? 1 (d) Positive acceleration with positive velocity? none (g) Negative acceleration with negative velocity? 4 (b) Uniform motion in the negative direction? 5 (e) Positive acceleration with negative velocity? 6 (h) Zero velocity and negative acceleration? 3 (c) Rest? 3 and 7 (f) Negative acceleration with positive velocity? 2 (i) Zero velocity and positive acceleration? none +𝑣 REST −𝑣 rest UM +𝑎 −𝑎 UM UM 3. The plot above shows the position vs. time of a particle. Indicate the interval over which the particle experiences the specified motion and then label that interval on the graph. When is the particle… (a) traveling in the positive direction? Label it! (b) traveling in the negative direction? Label it! B to E E to G (d) undergoing positive acceleration? Label it! (e) undergoing negative acceleration? Label it! B to C D to F (g) speeding up? Label it! B to C and E to F (h) slowing down? Label it! (c) at rest? Label it! A to B and E (f) undergoing uniform motion? Label it! A to B, C to D, and F to G D to E 4. Which point or points on the graph – if any – show instants at which there was… (a) Uniform motion in the positive direction? (b) Uniform motion in the negative direction? 3 7 (d) Positive acceleration with positive velocity? 2 (g) Negative acceleration with negative velocity? 6 (e) Positive acceleration with negative velocity? none (h) Zero velocity and negative acceleration? 5 (c) Rest? 1 and 5 (f) Negative acceleration with positive velocity? 4 (i) Zero velocity and positive acceleration? none Name: _______________________ Mr. Kepple Motion Graphs – Part 2 1D Kinematics – HW#3 𝑣 Date: ___________ Period: _____ +𝑣 −𝑣 −𝑣 rest +𝑣 rest +𝑎 −𝑎 rest +𝑎 UM +𝑎 𝑡 UM 1. The plot above shows the velocity vs. time of a particle. Indicate the interval over which the particle experiences the specified motion and then label that interval on the graph. When is the particle… (a) traveling in the positive direction? Label it! (b) traveling in the negative direction? Label it! 1-3, 9-12 0-1, 3-9 (d) undergoing positive acceleration? Label it! (e) undergoing negative acceleration? Label it! 0-2, 4-6, 8-10 2-4 (g) speeding up? Label it! (h) slowing down? Label it! 1-2, 3-4, 9-10 0-1, 2-3, 4-6, 8-9 (c) at rest? Label it! 1, 3, 9 (f) undergoing uniform motion? Label it! 6-8, 10-12 𝑣 𝑡 2. Which point or points on the graph – if any – show instants at which there was… (a) Uniform motion in the positive direction? G (d) Positive acceleration with positive velocity? F (g) Negative acceleration with negative velocity? C (b) Uniform motion in the negative direction? E (e) Positive acceleration with negative velocity? D (h) Zero velocity and negative acceleration? none (c) Rest? A (f) Negative acceleration with positive velocity? B (i) Zero velocity and positive acceleration? A 𝑥 −𝑣 +𝑣 REST rest 𝑡 −𝑎 +𝑎 UM −𝑎 UM 3. The plot above shows the position vs. time of a particle. Indicate the interval over which the particle experiences the specified motion and then label that interval on the graph. When is the particle… (a) traveling in the positive direction? Label it! (b) traveling in the negative direction? Label it! 4-10 0-4 (d) undergoing positive acceleration? Label it! (e) undergoing negative acceleration? Label it! 2-6 0-2, 8-10 (g) speeding up? Label it! (h) slowing down? Label it! 0-2, 4-6 2-4, 8-10 (c) at rest? Label it! 4, 10-12 (f) undergoing uniform motion? Label it! 6-8, 10-12 𝑥 𝑡 4. Which point or points on the graph – if any – show instants at which there was… (a) Uniform motion in the positive direction? (b) Uniform motion in the negative direction? E none (d) Positive acceleration with positive velocity? D (g) Negative acceleration with negative velocity? A (e) Positive acceleration with negative velocity? B (h) Zero velocity and negative acceleration? none (c) Rest? C and G (f) Negative acceleration with positive velocity? F (i) Zero velocity and positive acceleration? C Mr. Kepple Name: _______________________ Kinematics and Calculus FRQ 1D Kinematics – HW#4 Date: ___________ Period: _____ An object is moving along the -axis in a region where its velocity as a function of time is given as ( ) , where is in seconds and is in meters per second. When s, the object is observed to be at position 44 meters. (a) Determine the acceleration of the object as a function of time. 𝑑 𝑣(𝑡) 𝑑𝑡 𝑎(𝑡) 𝑑 ( 𝑑𝑡 𝑡) 𝑎(𝑡) (b) Determine the position of the object as a function of time. 𝑥(𝑡) 𝑥( ) 𝑣(𝑡)𝑑𝑡 2( 𝑥(𝑡) 𝑡 𝑡 +𝐶 𝑥(𝑡) 𝑡 𝑡2 + 1 ( ) 𝑡)𝑑𝑡 𝐶 (c) Calculate the initial position and the initial velocity of the object. 𝑥( ) 𝑥0 ( )2 + 1 ( ) 1 m 𝑣( ) 𝑣0 ( ) m/s (d) At what time does the object reach its maximum position? Position is at its maximum when the velocity is zero. 𝑣(𝑡) 𝑡 5s (𝑡) ( )2 + 𝐶 8+𝐶 1 m (e) Calculate the maximum position the object reaches. 𝑡2 + 1 𝑥(𝑡) 𝑡 𝑥(5) (5) 𝑥 (5)2 + 1 6 m (f) On the axes below, sketch graphs of the object’s position , velocity , and acceleration as functions of time . The three graphs should cover the same time interval and use the same scale on the horizontal axis. Be sure to label the initial velocity of each quantity. 𝑥 𝑥0 1 m 𝑂 𝑡 𝑣 𝑣0 m/s 𝑂 𝑡 𝑎 𝑂 𝑎 m/s2 𝑡