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Usain Bolt 100 m World Record Introduction: In this activity you will be analyzing the world record run from Usain Bolt in the 2009 Track and Field Championships. Procedure: Below is a data table showing Bolt's times at each 10 m spot along the track. What is the difference between speed and velocity? Speed is a scalar corresponding to velocity’s magnitude. Calculate the time it took bolt to run each 10 meter interval. Calculate the average velocity for each interval by dividing the displacement for the interval (10 m for each) by the interval time (in m/s and in km/h) Create a graph of position vs. time (Scale: x-axis 1cm = 1s ; y-axis 1 cm = 10m) Highlight the linear portion of your position vs. time graph and then do a linear fit to get the slope of this part of your graph. Create a bar graph of velocity vs. time (Scale: 1 bar = 1 interval = 1 cm ; 1 cm = 4m/s) NB: When creating a graph or a bar graph there are several things you mustn’t forget: the graph title, two axes, including axes labels and scale… Distance (m) 100 Bolt's 100m world record : Distance = f(time) 90 80 70 60 50 40 30 20 10 0 Time (s) 0 Speed km/h) 50,0 45,0 40,0 35,0 30,0 25,0 20,0 15,0 10,0 5,0 0,0 0 to 10 2 4 6 8 10 Bolt's 100m world record: AVG speed / 10 m interval Interval 10 to 20 20 to 30 30 to 40 40 to 50 50 to 60 60 to 70 70 to 80 80 to 90 90 to 100 Use your data table and graphs for Bolt's 100 m run to answer the questions given below: What is Bolt’s top speed for a 10 m interval? Bolt's Top Speed for a 10 m section of the race is about 12.3 m/s. How many of Bolt's intervals were run in times greater than 1.0 seconds? Bolt only ran 1 interval in times greater than 1.0 s. What is the slope of your position vs. time graph if you look only at points from 4.0s seconds and beyond? The slope is constant, corresponding to a constant velocity (≈12.1 m/s). What was Bolt's top speed in mph for a 10 meter interval? NB: 1 mile = 1609 m Imagine an object falling on the moon from a height of 100 m (supposing no friction). Assuming that moon’s gravity is 6 times less than on Earth, could Bolt complete his 100 m before this object landed? [No calculator!] Yes, Bolt would complete his 100 m before this object! For the object we have d = ½ x (9.8/6) x t² and then d(10s) ≈ 0.5x1.6x10²≈ 80m.