Car Rolling Friction: Answers to Questions

AI Thread Summary
Rolling friction for a car is calculated using the weight and the coefficient of friction, resulting in a total friction force of 294N for a 1000kg vehicle. If the torque on the wheels is less than or equal to this friction force, the frictional torque will match the opposing torque, preventing movement. Static friction depends on the opposing force, while kinetic friction remains constant regardless of speed. When braking, the direction of the frictional force reverses, affecting the car's motion. If the applied torque is insufficient to overcome the friction force, the car will not roll.
impel123
Messages
6
Reaction score
0
Hello guys,

I would like to help me with rolling friction on a car(i am building a project that simulates the forces
applied to a vehicle when it moves on a straight road http://rapidshare.de/files/40862186/Vehicle_Sim.zip.html).

So:

Engine has a torque at some RPM,and the torque goes to the wheels with gearbox.If car weights 1000kg,and
rolling friction coefficient is 0.03, then total friction force for all 4 wheels is 1000*9.81*0.03=294N.


1)what happends if torque on wheels from engine in certain RPM is 190N (<=294)?friction then is 0 or 190 or 294?
2)friction depends on speed?
3)when a apply brake,and brakes make car slows down with acceleration=9m/s^2,friction force changes direction?
4) if friction is 294N and car speed=0,and driver presses acceleration pedal but the torque on wheels is only 100N,
the car will never roll?

thanks a lot!
 
Last edited by a moderator:
Physics news on Phys.org
1) If friction is preventing the car from moving, then the frictional torque is equal to the torque it is acting against (190)
2) Static (unmoving) friction depends on the force it is opposing, because friction never adds energy to a system and can only oppose the other forces acting on it. Once the car is moving, the frictional force does not very with speed
3) Yes, when braking, the frictional force reverses direction
4) Unless the force of friction can be overcome, the car will not move
 
Thank You so much:smile:
 
Hi there, im studying nanoscience at the university in Basel. Today I looked at the topic of intertial and non-inertial reference frames and the existence of fictitious forces. I understand that you call forces real in physics if they appear in interplay. Meaning that a force is real when there is the "actio" partner to the "reactio" partner. If this condition is not satisfied the force is not real. I also understand that if you specifically look at non-inertial reference frames you can...
I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
Back
Top