C2H6

Graph One-dimension direction, all while remaining at positions that are positive. Slope Direction The direction of travel is indicated in these graphs by the sign of the slope. Recall from math that the si ise" divided by the "run", or Ax/At. In physics, our ere to plot a position (m) vs. time (s) graph, what would the units of the slope be? The sign of the slope is determined by carefully matching the 2 coor he graph. Thus, slope is AX = _2 1, where (t2. x2) represents n, and will be moving towards more negative values. The slope of an object's position versus * (m) What is the velocity of this object between 1 and 2 seconds? m/'s What is the velocity between 8 and 9 seconds? m/s At what time, if ever, is the velocity of the object 0 mis? If never, type 'neverSpeeding Up or Slowing Down An object that has a cur cated by a graph's turning point, if it has any. The slope of a curved line changes. It can be deter . which is the slope of a straight line to ve a sign that will indicate the direction of travel. This graph (above) represents an object that is There are three features to examine when examining a position-time graph. . Where the object is with respect to the coo spect to the coordinate system: above or below the axis shows where the object is located with respect to the defined origin. 2. The sign of the slope of the graph indicating the direction of motion. 3. Whether the slope is constant or changing, indicating constant speed, speeding up, or slowing down. Graph A shows an object that is moving with positive velocity. The position-time graph has positive slope and the object will move in a direction towards larger and larger positive values in the o e coordinate system. The object always has a positive position as it is always in the positive part of the coordinate system, or a eous slope/velocity goes from large positive numbers to small positive numbers through time. For Graphs B-H. click on the descriptions that match the corresponding graph. Graph B: Pos. Positions Pos. Velocity Speeding Up Neg. Positions Neg. Velocity Slowing Down Graph C: Pos. Positions Pos. Velocity Speeding Up Neg. Positions Neg. Velocity Slowing Down Graph D: Pos. Positions Pos. Velocity Speeding Up Neg. Positions Neg. Velocity Slowing Down Graph E: Pos. Positions Pos. Velocity Speeding Up Neg. Positions Neg. Velocity Slowing Down Graph F: Pos. Positions Pos. Velocity Speeding Up Neg. Positions Neg. Velocity Slowing Down Graph G: Pos. Positions Pos. Velocity Speeding Up Neg. Positions Neg. Velocity Slowing Down Graph H: Pos. Positions Pos. Velocity Speeding Up Neg. Positions Neg. Velocity Slowing Down--Select - Heading negative Starts heading positive and ends heading negative Not moving Speeding up Constant speed Starts heading negative and ends heading positive Slowing downVelocity vs. Time Graphs Preview Motion of an object in one dimension can also be represented by a graph of velocity vs. time (v-t). B C Which of these graphs shows an object traveling at a constant velocity? Choose all that apply. DA Which of these graphs have a constant slope? Choose all that apply. What are the units of the slope of a velocity va. time graphs if velocity has units of mis and time has seconds?Velocity vs. Time Graphs The units for a velocity vs. time slope are m/s/s. Remember that slope for a velocity-time graph will be - where the change in velocity. A v = v2-v, and t2 > t1 The slope of a v-t graph is the acceleration. The graph of a constant velocity object will have a slope of zero on a v-t graph because the velocity is not changing: a constant velocity object has zero acceleration. Similar to the definitions of negative and positive velocity on a position-time graph, a negative slope on a v- graph is negative acceleration and a positive slope is positive acceleration. A B CDEF Identify which parts of this discontinuous v-t graph have positive acceleration. Pick all that apply. The vertical ticks represent 3 mis and the horizontal ticks are 1 s. A m Which of these segments show when the object is speeding up? Pick all that apply. A B 0 Most of the examples in our introductory physics class will involve constant acceleration. Which of the following do you not expect to see for constant acceleration? (Hint: look carefully at what is plotted on the vertical axis.)