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Question 2.1 To optimise the vehicle's ability to coast, the resistance forces are the most important factors. The main variables are: • Aerodynamic: Coefficient of aerodynamic drag (Cd) • Rolling resistance: Coefficient of rolling resistance (Crr) Assume the following values for other parameters: Af 1.4 m2 vlow 2 m/s mveh 75 kg vhigh 6 m/s Tm 3 Nm GR 6 Using MATLAB (in the MATLAB Grader environment), produce code that determines the value of percentage time on for: a) Cd values between 0.08 and 0.3 in steps of 0.01. Set Crr to be 0.002. Show the results by plotting a graph of percentage time on against coefficient of drag (i.e. pcttime as the y-axis, and Cd as the x-axis). The y-axis should have the label 'Percentage Time On (%)' and the x-axis should have the label 'Coefficient of drag'. [3 marks] b) Crr values between 0.001 and 0.004 in steps of 0.0001. Set Cd to be 0.1. Show the results by plotting a graph of percentage time on against coefficient of rolling resistance (i.e. pcttime as the y-axis, and Crr as the x-axis). The y-axis should have the label 'Percentage Time On (%)' and the x-axis should have the label 'Coefficient of rolling resistance'. [3 marks] Based upon the results from a) and b): c) Explain the shapes of the graphs. [3 marks] d) Which variable out of Cd and Crr has the most significant impact (based upon the range of values used) on percentage of time on? [2 marks] e) Suggest optimal values for both Cd and Crr based upon the range of values used. [2 marks]