How do you use a graph to calculate average speed? - Answers

You first have to have an experiment done where you can obtain the variables "velocity" and "time". Your velocity is your speed. Once you've done an experiment, like running up stairs or walking from one end of a hall to the other, gather up your variables; How long it took you to finish the test (your time), and your speed (how fast it took you to do the test). TO GET THE VELOCITY: You have to divide your distance by time. So measure how far you traveled, and then divide that number by how long it took you to complete the test. You'll need to do complete multiple tests (around 7+ is a good number of tests) before you can find the average speed. After you've completed all your tests, make a graph with your velocities and your times by making velocities your Y-variable and the times your X-variables. Once you've plotted your graph (it should be a dotted line graph), measure the slope of the data, and you will have your average speed! (To measure the slope you have to have the change in distance and your change in time. Divide those two numbers and you'll get your average speed, which is how many metres you move per second in time.) Starting distance: 0 Ending distance: 20 Starting time: 0 Ending time: 4.72 Slope = D2 - D1 / T2 - T1 = 20 - 0 / 4.72 - 0 = 20 / 4.72 = 4.24 m/s In this example your slope would be 4.24, or 4.24 m/s, which is also your average speed.