All Questions
Tagged with classical-mechanics work
22
questions with no upvoted or accepted answers
13
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The role of the virtual work principle
Lanczos' masterpiece "The Variational Principle of Mechanics" has, on page 76, the following statement:
Postulate A (virtual work): The virtual work of the forces of reaction is always zero for any ...
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4
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1
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What does it mean for a force to 'produce' virtual displacement?
Book: Variational Principles of Mechanics by Lanczos, 1st edition, 1949.
Statement (page 80):
"Two systems of forces which produce the same virtual displacements are dynamically equivalent."...
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Constraint forces do no virtual work: does this always apply?
The thread title is my main question, but to give some context, I'll include a particular example that made me ask the question in the first place.
In Hand and Finch, a small block is on a ...
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1
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Vanishing virtual work done by non-holonomic constraints
I was reading classical mechanics by NC Rana. I was reading a topic on vanishing virtual work done due to constraint forces. How do you prove that the virtual work done by non-holonomic constraint ...
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Aren't the virtual work/virtual power principles in mechanics simply solving for the vector differential equation of motion in a preferred direction?
My conceptual understanding of the virtual work/virtual power principles is that, by hypothesizing "virtual displacements"/"virtual velocities", one can solve the equations of ...
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1
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2
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Law of Conservation of Energy ambiguity in Giancoli textbook
In my version of the textbook by Giancoli: Physics for Scientists and Engineers, in chapter 8, there is a formulation of the law of conservation of energy that seems unintuitive and correctable to me. ...
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0
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Are principle of virtual work and principle of minimum potential energy same? And how is it related to Calculus of variation?
I am studying Finite element method and Classical Mechanics. I have come across three important terms
Principle of virtual work (found in Classical Mechanics)
Principle of minimum potential energy (...
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1
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1
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Conceptual question about rotational and translational kinectic energy
My real life problem is to calculate initial translational and angular velocities of a vehicle in a loss of control to a stop (the vehicle will translate and rotate about it's center of mass.)
Initial ...
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Unrelated states in virtual work
I'm reading the Wikipedia article on virtual work, and there is the following quote:
Consider now the free body diagram of a deformable body, which is composed of an infinite number of differential ...
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1
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1
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Does measured mechanical power and work change between inertial frames?
Imagine a car A is accelerating.
Two observers at constant speed, B and C, analyse the change of A's kinetic energy over a same time interval.
B sees A going from 10 to 30 m/s
C sees A going from ...
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1
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Conceptual Difficulty About Work
So my issue is best explained with an example.
Let us consider a ring of mass $m$ and radius $R$ sliding down an incline of angle $\theta$ ($I = mR^2$). It starts from a height h, and we wish to ...
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1
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1
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139
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Virtual work of a moving surface on a particle constrained to it
I've only just begun reading through Goldstein's Classical Mechanics. This section is on D'Alembert's Principle and Lagrange's Equations. The following quote is from the beginning of the section.
...
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0
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Work done by rolling vs skidding friction force
Two identical bicycles having equal weight riders are traveling along a level road adjacent to each other with the same non-zero velocity. Bike A, (the "skidder"), applies the rear brake strongly ...
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1
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Drawbacks of Quasi-Static process for lifting a block
Definition of Quasi-static: A quasi-static process is a thermodynamic or mechanical process that occurs very slowly, allowing the system to remain in a state of equilibrium at all times.
While ...
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1
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Why is the force being the differential of a potential equivalent to it being a conservative force?
I was reading Goldstein's book on mechanics and came across this theorem:
$F(r) = - \nabla V(r)$ is a necessary and sufficient condition of the force field being conservative.
So far, I have ...
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1
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Is the definition of work related to the nature of the fundamental interactions?
I am having troubles trying to understand why is work defined as it is.
So, I know how work is defined: $W = \vec{F}\cdot{}\vec{d}$ (F is the force, d the displacement) and I am okay with it. This, ...
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Does this vector need to be fixed for the kinetic energy to be constant?
I was solving the following homework problem:
A force $\vec{F} = \vec{k} \times \vec{v}$ is applied to a particle of mass $m$. Here $\vec{k}$ is a fixed vector and $\vec{v}$ is the velocity of the ...
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1
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260
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Is impulse functionally equivalent to work and therefore expressible in Joules?
I am trying to understand things at at a fundamental and conceptual level.
Givens...
1 kg mass
Mass is at rest (relatively, of course)
Mass is on an idealized frictionless surface
1 N of force is ...
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3
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97
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Why the weight vector is perpendicular to the displacement of the object being moved by the tension force in the conical pendulum?
Can someone explain why, in the conical pendulum, the weight vector is perpendicular to the displacement of the object being moved by the tension force in the system? I understand that the tension ...
user282164
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Work and mechanical energy relationship for a rigid body
For a single particle in a conservative field, I know that the work done by an external non conservative force $W_n=\Delta M$ where $\Delta M$ is the total mechanical energy.
Is the same true for an ...
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-1
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Conservative forces and Variation
I am currently studying "Classical mechanics by Goldstein" and have just started. The book introduced something simple. For a conservative force, the work done in taking a mass from one ...
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3
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Why gravitational potential away from a planet increases?
textbooks----
"potential increases towards infinity and is maximum at infinity"
But that is true only when we are seeing potential w.r.t Earth
EXPLANATION---------
So , as we know that ...
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