All Questions
Tagged with classical-mechanics work
214
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Equation for Work required to achieve a certain velocity [closed]
If we are trying to find the work required to get an object moving at velocity $v$, and we start with $w = f\cdot d$, we can then make the following substitutions:
substitute $f$ with ma: $w = m\cdot ...
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Conditions for a force to be conservative
Taylor's classical mechanics ,chapter 4, states:
A force is conservative,if and only if it satisfies two conditions:
$\vec{F}$ is a function of only the position. i.e $\vec{F}=\vec{F}(\vec{r})$.
The ...
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Variable Exchange $F(t) \to F(x)$? I want the value of the work done by drag [closed]
I got a nonlinear equation, which describes the magnitude of a force as a function of time, but I don't know how to calculate the work done by the force. Given:
$$F(t) = kv(t)$$
with
$$v(t)= \left(1-\...
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3
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Defining potential energy in Taylor's Classical Mechanics
I'm trying to understand this sentence in introducing potential energy in John Taylor's book:
If all forces on an object are conservative, then can define a quantity called potential energy, $U (\...
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Simple Force/Work Problem
In "Thinking Physics" there is a question about pushing a barrel up a ramp. The barrel is 100 pounds and the ramp is 3 feet high and 6 feet on the hypotenuse. The question is how much force ...
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How is virtual work defined?
Let $S$ be a system with $g$ degrees of freedom, $\Sigma_g$ its configuration space and $\{q_i\}_{i=1}^g$ the lagrangian coordinates. If $P\in\Sigma_g$, we define a virtual displacement from $P$ as ...
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Net Work Done When Lifting an Object at a constant speed [duplicate]
I am confused about the amount of work done when lifting an object at a constant speed. If you find the work done by you on the object and the work done by gravity on the object and add them the net ...
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The work done by emptying a well full of water upto a certain height [closed]
Lets say we have a well full of water (For now lets say it is cylindrical) .Lets say its height is $h$$well$. The water is filled upto a height $h$$water$. The radius of the well (cylindrical) is $r$ ....
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Calculating work done vs. calculating final energy [closed]
I'm trying to solve for work after 2 seconds given $v(t)=3t^2$ and mass$=1kg$. There are 2 approaches:
Just calculate kinetic energy after 2 seconds: $E_k=.5*mv^2 = .5 *1 * (3*2^2)^2 = .5* 144 = 72J$
...
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Why is the work done by a block into a spring the same from the work done by the spring on the block?
In the following situation:
A 700 g block is released from rest at height h 0 above a vertical
spring with spring constant k = 400 N/m and negligible mass. The block
sticks to the spring and ...
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3
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Does work between 2 bodies depend on their relative speed?
Imagine a car standing on the road. Now the car starts to accelerate.
On the first part, the car accelerates from 0 m/s to 10 m/s.
Some of the fuel was used during this first part. let's call that ...
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Does work increases as accelaration increases?
If work is a product of force and displacement, and force increases as acceleration increases, does these mean that work is dependent on acceleration? For instance, if I lift a block faster, does this ...
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Does a planet do any work when it changes trajectory of spacecraft flying near it?
Let's say there is a spacecraft flying near a planet. It just flies near without orbiting the planet. Its trajectory changes as a result of planet's gravitational pull.
Does the planet do any work?
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Work done by constraint forces -- Generalisation
Consider the above scenario: In the subsequent motion, we need to find the work done by tension on the (trolley + mass) system.
Solution: Suppose at an instant, the velocity of the trolley (and hence ...
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The "coefficients" of virtual displacement in Goldstein's classical mechanics
In Goldstein's classical mechanics the following passage is confusing me:
We therefore have as the condition for equilibrium of a system that the virtual work of the applied forces vanishes: $$\sum_i ...
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