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Chapter 5: Chassis and Design 123Vehicle speed(mph) 10 20 30 40 50 60 70 80 90Tire rolling 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015resistance C rBrake and 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003steeringresistance C rTotal rolling 68.4 68.4 68.4 68.4 68.4 68.4 68.4 68.4 68.4force (lbs)Still air drag 2.76 11.05 24.60 44.19 69.05 99.43 135.35 176.78 223.73force (lbs)Relative wind 1.338 0.449 0.25 0.169 0.126 0.101 0.083 0.071 0.062factor C wRelative wind 3.70 4.96 6.21 7.47 8.73 9.99 11.25 12.51 13.77drag force (lbs)Total drag force, 74.86 84.40 99.47 120.07 146.19 177.83 215.00 257.69 305.91level (lbs)Total drag 77.85 87.78 103.45 124.87 152.04 184.95 223.60 268.00 318.15torque, level(ft-lbs)Sin f, f = Arc 0.0500 0.0500 0.0500 0.0500 0.0500 0.0500 0.0500 0.0500 0.0500tan 5% inclineCos f, f = Arc 0.9988 0.9988 0.9988 0.9988 0.9988 0.9988 0.9988 0.9988 0.9988tan 5% inclineIncline force 190.04 190.04 190.04 190.04 190.04 190.04 190.04 190.04 190.04WSin f (lbs)Rolling drag force 68.31 68.31 68.31 68.31 68.31 68.31 68.31 68.31 68.31C rWCos f (lbs)Total drag force, 264.81 274.36 289.43 310.02 336.14 367.78 404.95 447.64 495.865% (lbs)Total drag torque, 275.41 285.34 301.01 322.43 349.59 382.50 421.16 465.56 515.715% (ft-lbs)Sin (Arc tan 0.0996 0.0996 0.0996 0.0996 0.0996 0.0996 0.0996 0.0996 0.099610% incline)Cos (Arc tan 0.9950 0.9950 0.9950 0.9950 0.9950 0.9950 0.9950 0.9950 0.995010% incline)Incline force 378.52 378.52 378.52 378.52 378.52 378.52 378.52 378.52 378.52WSin f (lbs)Rolling drag force 68.06 68.06 68.06 68.06 68.06 68.06 68.06 68.06 68.06C rWCos f (lbs)Total drag force, 453.04 462.58 477.65 498.25 524.37 556.01 593.18 635.87 684.0810% (lbs)Total drag torque, 471.17 481.10 496.77 518.19 545.35 578.26 616.92 661.32 711.4610% (ft-lbs)(continued on next page)Ta b l e 5-10 Torque Required W orksheet for 1987 F ord Ranger Pickup at Different V ehicleSpeeds andInclines*