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Ole Forsell

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<Moved from a technical forum. Therefore no template.>I am currently analysing the forces acting on a moving vehicle. The vehicle is mounted on a rail with wheels on both upper and lower side of the rail with a spring increasing the reaction force, and thereby the friction. The vehicle should be designed to reach an acceleration, a, of 9 m/s

The vehicle have a mass, m, of 5 kg, and a cross-section area, A, of 0,04 m

Until now I have used the following equations:

Fnet = Ft + Fd + Fr

Where

Fnet: Total longitudinal force required to reach the acceleration

Ft = Traction force from the driving wheel

Fd = drag force

Fr = rolling resistance

From this I get Fnet = 57,56 N

Do I need to include the friction force in this equation?

From this I have used two different formulas to calculate the Torque required to reach the needed acceleration: T = Fnet*r and T = I*alpha.

Where

I: moment of inertia of the wheel

alpha: angular velocity

I know the second equation is wrong, since only parameters for the driving wheel is included, but i have no idea how to use this for the whole vehicle.

With the first equation I get a required torque of approximately 6,10 Nm. I do not believe this is correct, and I think I am missing out on something.

I've been searching the forum for this problem, but I have not yet found an answer to this specific problem.

^{2}.The vehicle have a mass, m, of 5 kg, and a cross-section area, A, of 0,04 m

^{2}. The wheel have a radius, r, of 0,106 m.Until now I have used the following equations:

Fnet = Ft + Fd + Fr

Where

Fnet: Total longitudinal force required to reach the acceleration

Ft = Traction force from the driving wheel

Fd = drag force

Fr = rolling resistance

From this I get Fnet = 57,56 N

Do I need to include the friction force in this equation?

From this I have used two different formulas to calculate the Torque required to reach the needed acceleration: T = Fnet*r and T = I*alpha.

Where

I: moment of inertia of the wheel

alpha: angular velocity

I know the second equation is wrong, since only parameters for the driving wheel is included, but i have no idea how to use this for the whole vehicle.

With the first equation I get a required torque of approximately 6,10 Nm. I do not believe this is correct, and I think I am missing out on something.

I've been searching the forum for this problem, but I have not yet found an answer to this specific problem.

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