I have been working on this for a while. 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.(adsbygoogle = window.adsbygoogle || []).push({});

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}

So far, I have gotten this for one scenario, going 20 mph in sand:

F_{TR}=(7100)[sin(0)+0.35]+[(7100)(0.35(29.3/35))+(0.0718/2)(0.75)(22)](29.3)^{2}=1.06037E6

I used 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

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Force of Tractive Resistance on a Vehicle

**Physics Forums | Science Articles, Homework Help, Discussion**