Driving a Car on a Straight Road: Analyzing Forces

[impel123]

I am building a project,where you drive a car on a straight road.

The car has 3 kinds of forces:
1)Torque of engine in the wheels
2)Friction on the tyres
3)Force due to air resistance

If a car accelerating,and is front wheel drive,then the 2 front wheels have these forces:

<-------(Engine Torque)-------O------(Static friction)-------------->

and the rear wheels

<-------(Rolling friction)-------O


so car has these forces:

<---(Engine torque,rolling friction,air resistance force)--(CAR)--(Static friction force)---->

So,Whats the total force?

F=engine_torque-air_resistance-rolling_friction-static_friction ?

I read that static friction causes movement...so static friction is equal to engine torque?I am comfused.

 

[OmCheeto]

I am building a project,where you drive a car on a straight road.

The car has 3 kinds of forces:
1)Torque of engine in the wheels
2)Friction on the tyres
3)Force due to air resistance

If a car accelerating,and is front wheel drive,then the 2 front wheels have these forces:

<-------(Engine Torque)-------O------(Static friction)-------------->

and the rear wheels

<-------(Rolling friction)-------O


so car has these forces:

<---(Engine torque,rolling friction,air resistance force)--(CAR)--(Static friction force)---->

So,Whats the total force?

F=engine_torque-air_resistance-rolling_friction-static_friction ?

I read that static friction causes movement...so static friction is equal to engine torque?I am comfused.

I think it would make the problem more clear if you think of engine torque and static friction being in the same direction.

<---(Engine torque ~ Static friction force)--(CAR)--(rolling friction, air resistance)---->

 

[impel123]

so,if engine torque on front wheels<=static friction then

F_total=Engine_torque-air_resistance-rolling_friction_in_rear_wheels

else ,if engine torque on front wheels>static friction then

F_total=Kinetik_friction_force_in_front_wheels-air_resistance-rolling_friction_in_rear_wheels


When car speed=0,what is the minimum engine torque to start the car to move?

F_minumum=rolling_resistance_rear_wheels+x
where x is friction resistance on the front wheels.

What is the x?rolling friction again?

 

[OmCheeto]

so,if engine torque on front wheels<=static friction then

F_total=Engine_torque-air_resistance-rolling_friction_in_rear_wheels

It might also be a good idea to stop referring to the force as static friction.
Although technically correct, it's a bit confusing, as evidenced by your following statement:

else ,if engine torque on front wheels>static friction then

If the torque exceeds the static friction then you no longer have static friction, ie. your wheels will spin and you will have kinetic friction.

F_total=Kinetik_friction_force_in_front_wheels-air_resistance-rolling_friction_in_rear_wheels

When car speed=0,what is the minimum engine torque to start the car to move?

It would be equal to the force required to move the car.

F_minumum=rolling_resistance_rear_wheels+x
where x is friction resistance on the front wheels.

What is the x?rolling friction again?

Rolling friction is the resistance of a wheel being rolled over a surface.

 

[impel123]

I can't understand what is the minimun engine torque required to move the car,if initialy car speed=0..there is no resistance?

when car speed is >0 then the rear wheels have rolling friction,and the front wheels static friction so

if speed>0 then
Ftotal=Engine_torque-air_resistance-rolling_friction_rear_wheels

else is speed =0 then
Ftotal=Engine_torque

Is this right?

 

[OmCheeto]

I can't understand what is the minimun engine torque required to move the car,if initialy car speed=0..there is no resistance?

There is always resistance.

when car speed is >0 then the rear wheels have rolling friction,and the front wheels static friction so

The front wheels also have rolling friction.

if speed>0 then
Ftotal=Engine_torque-air_resistance-rolling_friction_rear_wheels

Basically. Yes.

else is speed =0 then
Ftotal=Engine_torque

Is this right?

I do not understand the question.

 

[impel123]

then,if and front wheels and rear wheels have rolling resistance,when speed>0

Ftotal=Engine_torque-air_resistance-front_wheels_rolling_resistance-rear_wheels_rolling_resistance


if speed=0,which is the minimum engine torque required to start the car to move?

Why don't you answer my questions?

I need to know which are the forces in the car when speed>0 and which is the minimun
engine torque required to move the car if speed=0.

There are 4 kinds of forces:
1)engine torque
2)rear_wheels rolling resistance
3)front wheels rolling resistance
4)air resistance

Give me an answer please...