Distance-Time Graphs Applied Physics 11
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
Time (s)Distance (m)
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.
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.
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.
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
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
p 364 Time (min)Distance (km) Time (min) Distance (m)
Time (min) Distance (km) Time (s) Distance (km)