All Questions
171
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I am confused about potential energy and work done by a force [closed]
Potential energy is the energy contained in a body due to its position. But I don't understand it because when object falls, PE= mgh and work done by gravity, is - mgh. So what is the difference other ...
- 91
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113
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Paradox? Why does energy conservation appear to be violated in this simple geared system?
While answering a question about gears and levers, I found I could not get the work in to equal the work out in this simple gear system illustrated below:
The gears are set up to replicate a lever, ...
- 6,102
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2
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59
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Shape of graph of energy in S.H.M
I'm confused to whether the graph of KE/PE of a simple harmonic motion system is sinusoidal or not
those are my best sketches but if unclear, the blue one is in a shape of a sine wave.
this question ...
- 117
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76
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Question related to conservation of energy
Here is a textbook passage that I have trouble understanding. It is taken from Classical Mechanics by Tom WB Kibble and Frank H Berkshire.
We consider first a particle moving along a line, under a ...
- 11
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35
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Change in Work-Energy Theorem
We have Work-Energy Theorem as follows:
$$W_c +W_{nc} + W_{ext} = ΔK$$ $-(1)$
, where $W_c$ = work done by conservative forces,
$W_{nc}$ = work done by non-conservative forces, $W_{ext}$ = work done ...
- 349
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4
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149
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Work and Energy Theorem - Theoretical Question
The work energy theorem states that for a given object
∆ Kinetic Energy = Work done by all forces ( Conservative, Non Conservative, External )
Here ,
Suppose if ∆KE = 0 , Potential energy has changed
...
1
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3
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134
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Why do things always want to reduce their energy? [duplicate]
Every object wants to reduce its potential energy, but why is that so? Does it have an explanation, or is it just a law we accept?
- 53
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If a car is *accelerating* uphill, does it *gain* kinetic energy?
I had an exam yesterday on physics (9th Grade), there was a question that confused me a lot. It said: "If a Gas Car is accelerating uphill, what happens to its G.P.E and K.E?"
A: It loses ...
- 61
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61
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Conservative force and change in the mechanical energy
Why is work done by a conservative force equal to change in the potential energy only? Why doesn't it account for all mechanical energy, what about kinetic energy?
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48
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Work And Energy: Conceptual Potential Energy Doubt
Our teacher told us that objects store potential energy in them according the position of the object above the ground because of gravitational force.
Like we are holding a box up and it stores ...
-1
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3
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426
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How does gravitational potential energy work in a very large distance?
Consider a thought experiment (that I made when I was in high school) involving a universe with only two objects: a massive planet and a small asteroid. Initially, they are millions of light-years ...
- 109
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189
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Where does an object get its energy from and what does it mean?
It is stated that an object in motion acquires "kinetic energy" while an object under the influence of gravity when raised to a height acquires "potential energy" but I have a ...
- 442
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84
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Why Doesn't the Amount of Work Determine the Elastic Potential Energy in Springs and Gravitational Potential Energy? [closed]
Why isn't the amount of work done on the spring the determining factor for the amount of elastic potential energy stored in a spring?
I learned that the change in potential energy is a result of the ...
- 53
0
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2
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44
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Potential energy separately for each object
Potential energy change is :
$\Delta U = -W_{int}$ where $W_{int}$ is the internal forces.
For the ball which is falling down towards earth, we can write:
$\Delta U = -(W_{earth} + W_{ball}) = -(K_{...
- 137
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2
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55
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Work done by gravity confusion
Say we had an object at height $h$ in a gravitational field, and of mass $m$, its GPE would equal $mgh$, now say we dropped it and it fell a distance of $h$, the work done on the object would be equal ...
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