All Questions
Tagged with classical-mechanics work
214
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Is net force conservative?
From the work-energy theorem, $$\int_{C}^{}\vec{F}\cdot d\vec{r}= \frac{1}{2}mv^2_f -\frac{1}{2}mv^2_i$$
Is velocity the gradient of position, and if so, does that make this force a conservative ...
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In order for a force to be derived from the gradient of a potential energy, does the work done by such a force need to be invariant of the path?
Suppose a force $\mathbf{F} = \mathbf{F}(\mathbf{r}, t)$ where $\mathbf{r}$ is a three dimensional space vector and $t$ is time.
I understand that in order to a force be conservative two conditions ...
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Is the force required to push a wheelchair over a curb proportionally the same as to pulling it over the curb?
I measured the force required to pull a wheelchair over a curb using a winch and a digital fish scale. Is it valid to claim that this condition would be comparable to the force required to push the ...
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What is the physical intuition behind this energy conservation theorem?
I'm reading Quantum Theory for Mathematicians, by Brian C. Hall. Although the book is about Quantum Mechanics, it's chapter 2 is actually about Classical Mechanics, in which I encountered the ...
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Can Lagrange's equation be used if the virtual work done by constraint forces is not zero?
I'm learning analytical mechanics and was just introduced to d’Alembert’s principle, which I know is only valid when constraint forces' virtual work is zero. My question is, does this restriction also ...
- 207k
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Work done in sliding a block across a table, as seen in different inertial frames
Suppose, I'm pushing a block across a smooth table.
The length of the table is $d$, and the force that I applied is $F$.
According to an observer at rest, standing next to the table, the work done is $...
Buzz♦
- 16.3k
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Kinetic energy constant, but net Work done is not $0$
Suppose I have two objects of equal mass and volume, in space, in contact with one another.
The two objects exert equal and opposite gravitational force on each other. Let us apply a force $F$ on one ...
- 103k
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Work done on an object whilst lifting it
Imagine to lift an object with mass $m$ from height $h_1$ to height $h_2$ and neglect the friction with air. How much work have you done on the object?
My answers (big doubt in the second one!):
...
- 57.2k
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A simple doubt regarding spring potential energy
A conceptual problem. Suppose we have a spring whose stiffness constant is $k$. The spring is attached to a wall and the other end is fastened to a block. If we pull the block by an external force ...
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How is virtual work defined?
Let $S$ be a system with $g$ degrees of freedom, $\Sigma_g$ its configuration space and $\{q_i\}_{i=1}^g$ the lagrangian coordinates. If $P\in\Sigma_g$, we define a virtual displacement from $P$ as ...
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Can average power be non zero, but instantaneous power be zero
Q. A wind-powered generator converts wind energy into electric energy, Assume that the generator converts a fixed fraction of wind energy intercepted by its blades into electrical energy. For wind ...
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If the curve a particle moves in when calculating work is dependent on the force itself, why don't we find this path before doing work calculations?
I am having some confusion getting my head around work done by a general force on a curve. Lets say I had some mass in space so we aren't considering gravitational potential, if I apply some force ...
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Definition of Power
I wanted to clear my doubts regarding the true definition of power. Imagine a mass falling from a height and reaching the ground thanks to gravity. The power of this event would be the work done by ...
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Hyperelastic solids: why cannot the work in a closed process be negative?
While introducing the theory of hyperelastic solids, our professor gave the following example.
"Suppose to have a rubber which is undeformed. Then stretch it, and then release it. The final ...
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Is the value of the work done by the forces acting on a rigid body frame dependent?
I was going through the definition of "Work of Forces Acting on a Rigid Body" in Wikipedia .
Here they have mentioned that work done can be calculated by taking any reference point on the ...
