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4 votes

Physical meaning of line integral involving force

A conservative force is one for which the work done between any two points is path-independent. In general, the work done by a force between two points depends on the path taken. Think about the work ...
Ben H's user avatar
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3 votes

Work and Energy Theorem - Theoretical Question

∆KE = 0 , Potential energy has changed , what does the given formula suggest? It suggests that the net work done by conservative and non conservative forces is zero and that at least one of the ...
Bob D's user avatar
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3 votes

Is holding a falling object the same effort as lifting it?

Why do I have the impression that it takes more effort to lift than to retain the fall...? Because it does take more energy to lift it. A table can hold a heavy object above the floor without ...
Solomon Slow's user avatar
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1 vote
Accepted

Electric car battery weight: understand question

How data about car's ability to reduce speed from 100 to 80 can help with battery weight? Is it relevant at all to the question? A electric car has to use the energy in its batteries to counteract ...
Cort Ammon's user avatar
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1 vote

Defintion of gravitational potential

The second definition is incorrect and so that answers a number of your questions. First start by defining the system which in this case is the "unit mass" and the masses causing the ...
Farcher's user avatar
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1 vote
Accepted

Is holding a falling object the same effort as lifting it?

One of the most frustrating parts about teaching physics is that it's so hard to make examples involving the human body. The human body so chock full of complex higher order effects that often our ...
Cort Ammon's user avatar
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1 vote

Why is the work done by an expanding ideal gas $\textbf{P}_{ext}\Delta V$?

Word done by the gas on the piston (or deformable wall) is $p_{int} \Delta V$, and work done by the piston on the outside atmosphere of pressure $p_{ext}$ is $p_{ext}\Delta V$. The difference $(p_{int}...
Ján Lalinský's user avatar
1 vote

Physical meaning of line integral involving force

Whatever closed path an object takes, the total work on it from a conservative force will be zero.
Sahand Tabatabaei's user avatar
1 vote

Work and Energy Theorem - Theoretical Question

The formula suggest that when $\Delta K.E. = 0$, then net work by all forces is zero. In case of the body raised to height $x$, work of the raising force is $mgx$, work of the gravity force is $-mgx$, ...
Ján Lalinský's user avatar
1 vote

Work and Energy Theorem - Theoretical Question

Change in kinetic energy of a particular object equals the sum of work done on the kinetic energy associated with a particular object. This is just a restatement of the conservation of energy plus the ...
g s's user avatar
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1 vote

Heat generated is zero even when current is passed through wire

You just need to write the governing equations of the system, for both the electromagnetic and the mechanical part of the system. Flat capacitor Before moving on, let's recall some relations about a ...
basics's user avatar
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