1. Distance-Time Graphs Applied Physics 11

2. Distance-Time Graphs  Distance-time graphs are a way to visually show a collection of data.  They allow us to get a visual understanding of speed.  X-axis  time  Y-axis  distance

3. Time (s)Distance (m) 00 113 225 340 451 566 678

4. Slope  The proper equation for a line is y=mx + b  The y is the dependant variable (on y -axis) The x is the independent variable (on x-axis) The m is the slope of the line The b is the y intercept of the line.

5. Slope in a distance-time graph  In a distance-time graph the equation changes from  y= mx + b  d = vt  d is the dependant variable, lying on the y axis.  t (time) is the independant variable and lies on the x axis.  v (speed) is the slope of the line.  0 (the initial distance) is the y intercept.

6. Slope and Speed  In a distance time-graph, the slope determines the speed.  The steeper the slope, the greater the speed.  The object shown in graph A is travelling at a greater speed. It is covering a greater distance in a shorter time.

7. Finding speed from slope  Slope (or v) is equal to:  y/ Δ x  Δ d/ Δ t  Change in distance/change in time  RISE over RUN

8. Rise over Run  Δ d = d 2 –d 1  Δ d = 7.7km - 1.9km  Δ d = 5.8km  Δ t = t 2 – t 1  Δ t = 11.2min - 2.7min  Δ t = 8.5min  v = Δ d/ Δ t  v = 5.8/8.5  v=0.68km/min

10. p 364 Time (min)Distance (km) 00 11.0 21.8 32.9 44.2 55.0 65.9 76.9 88.2 99.2 1010.0 Time (min) Distance (m) 0 1 2 3 4 5 6 7 8 9 10

11. Time (min) Distance (km) 00.0 2.02.4 4.04.8 6.07.2 8.09.6 10.012.0 14.4 0 1 2 3 4 5 6 7 8 9 10 11 12 13 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Time (s) Distance (km)