(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I working on this for a high school thesis. I am trying to find the power required to move a 7100 lb vehicle over a variety of scenarios, but am having trouble calculating the force of tractive resistance.

2. Relevant equations

I found what i thought was a pretty exhaustive equation for the force of tractive resistance:

F_{TR}=mg[sin[itex]\alpha[/itex]+C_{0}sgn(V)]+sgn(V)[mgC_{1}+([itex]\rho[/itex]/2)C_{D}A_{F}]V^{2}+ma

where:

C_{0}=dimensionless coefficient of rolling resistance

[itex]\alpha[/itex]=the angle of the surface the vehicle is navigating

C_{1}=Coefficient of rolling resistance while in motion, calculated by (when C_{0}=0.01) C_{1}=C_{0}(V^{2}/100)

[itex]\rho[/itex]=air density (lb/ft^{3}

C_{D}=drag coefficient

A_{F}=frontal area of the vehicle (ft^{2})

V=velocity (fps)

g=32fps^{2}

3. The attempt at a solution

For my first scenario, finding F_{TR}when the vehicle is going 20mph in sand, I plugged in these numbers and got:

F_{TR}=(7100)(32)[sin(0)+0.35]+[(7100)(32)(0.35(29.3/35))+(0.0718/2)(0.75)(22)](29.3)^{2}=5.72299(10^7)

I used 32fps^{2}as the acceleration of gravity, 29.3fps as velocity because that would give me the answer in ft/lbs, and calculated C_{1}=0.35(29.3/35) because I figured '100' would change based on C_{0}. I also thought this number was astronomically large, especially since it would be multiplied by velocity to find the required power to meet the scenario requirements. I have also donr the same with several other scenarios, and gotten really big numbers

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# Homework Help: Finding the force of Tractive resistance on a vehicle

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