Name: bicycle torque and moment about an axis
Uploaded: 2023-09-22T11:49:21.000Z
Duration: 1 min 28 s
Channel: JoVE

Considera un ciclista che va in bicicletta e applica forza sul pedale per girare la ruota. Quando viene esercitata una forza sul pedale, la catena attaccata esercita una forza sugli ingranaggi della ruota. La ruota ruota attorno al suo asse, quindi l'asse di rotazione passa attraverso di essa.
Il momento di una forza lungo l'asse misura quanto la forza provoca la rotazione di un oggetto attorno a un punto o asse specifico.
In questo caso, la ruota ruota attorno all'asse y nel piano x-z. Qui, il braccio del momento o la distanza perpendicolare tra l'asse di rotazione e la linea di azione della forza è il raggio degli ingranaggi.
Quindi il momento di una forza attorno all'asse y è uguale a Frsinθ.
Poiché la forza è tangenziale, l'angolo tra il vettore di forza e il raggio è di 90 gradi.
In una bicicletta, il momento di forza può essere moltiplicato per la velocità angolare dell'asse per ottenere la potenza generata dalla rotazione della ruota.

<ol>
	<li>Hibbeler, R.C. (2016). Ingegneria Meccanica \u2012 Statica e Dinamica. Hoboken, New Jersey: Pearson Prentice Hall. pagine 145.</li>
</ol>

momento di una forza su di un asse: scalare

Moment of a Force About an Axis: Scalar

Il momento di una forza su di un asse è un concetto fondamentale nella meccanica che aiuta a determinare il moto rotazionale di un oggetto intorno ad un punto o ad un asse specifico. Il momento di una forza può essere calcolato mediante un'analisi scalare, che prevede la considerazione della distanza perpendicolare tra l'asse di rotazione e la linea di azione della forza, o semplicemente il braccio di leva.

Per comprendere meglio il concetto di momento di una forza, consideriamo l'esempio di un ciclista che guida una bicicletta. Quando il ciclista esercita una forza sul pedale, la catena collegata esercita una forza sull'asse della ruota, causandone la rotazione. Qui, l'asse di rotazione passa attraverso l'asse della ruota e il braccio di leva è il raggio dell'asse. In questo caso, il momento della forza sull'asse di rotazione è dato da:

<img alt="Equation 1" src="/files/ftp_upload/14258/14258_Equation_1v2.svg" style="text-align: center; height: 13px;" />

dove F è la forza applicata, r è il raggio dell'asse e θ è l'angolo tra il vettore della forza e il raggio. Poiché la forza è tangenziale, l'angolo tra il vettore della forza e il raggio è di 90 gradi.

In una bicicletta, il momento di una forza può essere moltiplicato dalla velocità angolare dell'asse per ottenere la potenza generata dalla rotazione della ruota. Il momento di una forza è essenziale nella progettazione di varie strutture e macchine, incluse biciclette, automobili e aeromobili, per garantirne la stabilità e la sicurezza.

Momento di una Forza su di un Asse: Scalare

Il momento di una forza attorno a un asse è un concetto cruciale in meccanica che aiuta a determinare il movimento rotatorio di un oggetto attorno a un punto specifico o ...

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Mechanical Engineering

Ingegneria Meccanica

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Force System Resultants

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bicycle torque and moment about an axis

The moment of a force about an axis describes how a force can make an object turn around a fixed line. In scalar analysis, the moment is found from the perpendicular distance between the axis of rotation and the line of action of the force. That distance is called the moment arm.

A bicycle gives a clear example of this idea. When the cyclist pushes on the pedal, the chain applies a force to the wheel’s axle and makes it rotate. The axis of rotation passes through the axle, and the moment arm is the axle radius.

For this case, the moment of force about the axis depends on the force, the radius, and the angle between the force vector and the radius. Because the force is tangential, that angle is 90 degrees. The moment of force can also be multiplied by the angular velocity of the axle to find the power produced by the wheel rotation.

This concept is important in the design of bicycles, automobiles, and aircraft. Engineers use it to help maintain stability and safety in these machines and structures.

Bicycle Torque and Moment About an Axis

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Learn how the moment of a force about an axis is found with scalar analysis, using a bicycle axle example and its link to rotational power.

Bicycle Torque and Moment About an Axis | JoVE K12

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Bicycle Torque and Moment About an Axis

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