Name: gravitational and elastic energy stored
Uploaded: 2023-09-22T11:49:37.000Z
Duration: 1 min 9 s
Channel: JoVE

L'energia potenziale è la capacità di un corpo di svolgere un lavoro grazie alla sua posizione.
La variazione di energia potenziale gravitazionale è il negativo del lavoro svolto su un corpo con la forza, uguale e contraria al suo peso, nel portare il corpo in una posizione specifica da una posizione di riferimento o dato in cui l'energia potenziale gravitazionale è considerata nulla.
Sollevando un corpo, il lavoro svolto dalla forza gravitazionale è negativo, e quindi la sua energia potenziale aumenta. Spostando il corpo verso il basso, si osserva il contrario.
L'energia potenziale elastica è il negativo del lavoro svolto a causa della forza di ripristino generata in un corpo elastico deformato che cerca di ripristinare la sua posizione non deformata.
Per una molla compressa, la variazione dell'energia potenziale elastica è positiva, mentre il lavoro svolto dalla forza della molla sulla massa è negativo. Lo stesso si osserva quando la molla viene allungata da una posizione non deformata.
Se sia la forza gravitazionale che quella elastica agiscono su un corpo, l'energia potenziale è la somma di entrambe le energie.

<ol>
	<li>Hibbeler, R.C. (2016). Ingegneria Meccanica: Statica. Quattordicesima edizione, New Jersey: Pearson. Pagine 598-599.</li>
	<li>Meriam, J.L., Kraige, L.G. e Bolten, J.N. (2016). Meccanica ingegneristica: statica e dinamica. Ottava edizione, Singapore: John Wiley & Sons. Pagine 411-413.</li>
</ol>

energia potenziale

Potential Energy

Una forza conservativa, come la forza gravitazionale o elastica, conferisce al corpo la capacità di compiere lavoro. Questa capacità, misurata come energia potenziale, dipende dalla posizione o "posizione" del corpo rispetto a una posizione di riferimento fissa o datum. L'energia potenziale gravitazionale, viene considerata zero nel punto di riferimento. Supponiamo che un corpo si trovi ad una certa distanza verticale sopra un riferimento orizzontale fisso o datum. In tal caso, il peso del corpo ha energia potenziale gravitazionale positiva poiché ha la capacità di compiere lavoro positivo quando il corpo viene risposto al datum. Allo stesso modo, se il corpo si trova ad una distanza verticale al di sotto del datum, l'energia potenziale gravitazionale è negativa poiché il peso compie lavoro negativo quando il corpo viene risospeso al datum.

Se l'altezza viene presa come zero al datum e la distanza verticale verso l'alto viene considerata positiva, allora ad una certa altezza sopra il piano datum, l'energia potenziale gravitazionale viene espressa come il prodotto del peso del corpo per la sua altezza dal piano datum. Matematicamente, ciò viene espresso come segue:

<img alt="Equation 1" src="/files/ftp_upload/14358/PT_14358_Equation_1.svg" style="text-align: center; height: 15px;" />

Se il corpo si trova ad una certa distanza al di sotto del piano datum, la sua energia potenziale gravitazionale diventa negativa. Si noti che il piano datum per l'energia potenziale zero è arbitrario poiché non influisce sul cambiamento dell'energia potenziale.

Il lavoro compiuto su un corpo elastico viene immagazzinato nel corpo sotto forma di energia potenziale elastica. Questa energia è disponibile per compiere lavoro su un altro corpo mentre allevia la sua compressione o estensione. Quando una forza comprime una molla, causa uno spostamento x, che è direttamente proporzionale alla forza applicata. L'energia potenziale elastica della molla per una compressione di x è il lavoro totale svolto sulla molla ed è espresso come segue:

Quando una molla viene stirata, la forza agisce nella direzione dello spostamento, compiendo quindi lavoro positivo sulla molla e aumentando la sua energia potenziale. Lo stesso si osserva quando una molla viene compressa dalla posizione non deformata.

Energia potenziale

Una forza conservativa, come una forza gravitazionale o elastica, conferisce al corpo la capacità di svolgere un lavoro. Questa capacità, misurata come energia potenziale, ...

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gravitational and elastic energy stored

Gravitational and elastic potential energy are forms of stored energy from conservative forces. A conservative force, such as gravity or an elastic force, gives a body the capacity to do work. This capacity is measured as potential energy and depends on the body’s position relative to a fixed reference point, or datum.

For gravitational potential energy, the datum is the level where the energy is taken as zero. If a body is above this reference plane, its weight has positive gravitational potential energy because it can do positive work as the body moves back down to the datum. If the body is below the datum, the gravitational potential energy is negative because the weight does negative work as the body is moved up to the reference level.

If height is measured upward from the datum as positive and zero is set at the reference plane, gravitational potential energy equals the body’s weight multiplied by its height. If the body is below the datum plane, the value becomes negative. The choice of zero potential energy is arbitrary, because only the change in potential energy matters.

Elastic potential energy is stored when work is done on an elastic body, such as a spring. This stored energy can later do work on another body as the spring returns toward its original shape. When a force compresses a spring, it produces a displacement x that is directly proportional to the applied force, and the elastic potential energy is the total work done on the spring.

A stretched spring also gains elastic potential energy because the force acts in the same direction as the displacement and does positive work on the spring. The same increase in potential energy is seen when a spring is compressed from its undeformed position.

Gravitational and Elastic Energy Stored

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Gravitational and elastic potential energy are forms of stored energy from conservative forces. A conservative force, such as gravity or an elastic force, gives a body the capacity to do work. This capacity is measured as potential energy and depends on the body’s position relative to a fixed reference point, or datum. For gravitational potential energy, the datum is the level where the energy is taken as zero. If a body is above this reference plane, its weight has positive gravitational...

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Gravitational and Elastic Energy Stored | JoVE K12

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Gravitational and Elastic Energy Stored

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