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Minimizing the action - particle in a potential well

About change of motion: When an object is in a situation where there is a gradient in the potential then the object will accelerate down the potential gradient. Given that acceleration: the stationary ...
• 22.2k
Accepted

Minimizing the action - particle in a potential well

The principle of least action is poorly named, because often the classical solution corresponds to a saddle point, and not actually a minimum of the action. The condition that you use to derive the ...
• 52.3k

Why does acceleration seem not to be the gradient of gravitational potential?

In fact, this seems to be a universal and a very logical rule since potential is like energy concentration- masses are accelerated by the negative of the gradient of energy too. To move something of ...
• 514
1 vote
Accepted

A man standing in an elevator at the third floor of a building. What is the primary factor that determines the man's kinetic energy?

First of all, kinetic energy (KE) is reference frame dependent. In the frame of the elevator, as long as the man moves with the elevator, the man's KE will always be zero. That said, in any other ...
• 75.7k

A man standing in an elevator at the third floor of a building. What is the primary factor that determines the man's kinetic energy?

The question is a bit misleading so let's go straight to it. If the elevator's speed is $v = 0$, then the mass has no effect whatsoever and $v$ is the "primary factor" causing $K_E = 0$ If ...

Gravitational potential energy of a water column

The velocity decreases as the column height falls The total energy contained in the column is $mgh \over 2$. So, if we pull the plug and let the column drain out, then the total kinetic energy must be ...
• 346
Lets consider a cylinder full of water that is 100 metres high with a cross sectional area of 2 $m^2$ so the volume of water is $200 m^3$ and the mass is 200 tonnes. The initial potential energy of ...