All Questions
33
questions
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Question about Problem $12$ in Chapter $11$ from Kibble & Berkshire's book
I write again the problem for convinience:
A rigid rod of length $2a$ is suspended by two light, inextensible strings of length $l$ joining its ends to supports also a distance $2a$ apart and level ...
5
votes
3
answers
2k
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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
0
votes
1
answer
106
views
Change in potential and kinetic energy after a photon is absorbed by a electron
This is a question from the AP Physics 2 2022 FRQ. Why does the potential energy of the atom and the kinetic energy of the electron decrease after a photon is absorbed? Shouldn't both of them increase?...
- 3
1
vote
1
answer
26
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Right displacement in spring potential energy [closed]
I have a doubt in general, the above problem is an example.
Here , the elastic string can be treated as a spring and we know the potential energy of a spring is $\frac{1}{2} k (x_f-x_i)^2$
So , ...
- 11
0
votes
1
answer
205
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Energy released from destruction of an object [closed]
In the movie ��Star Wars: A New Hope”, Luke Skywalker blows up the „Death Star‟. Assume
that the „Death Star‟ is a perfectly spherical spaceship with uniform mass distribution. The mass
of „Death Star‟ ...
- 3
1
vote
3
answers
1k
views
A rolling stone on a rollercoaster
A ball rolls from point $A$ ($v_0 = 0 \; m / s$) to the right along a friction-less path. We can then calculate the speed of the ball at the points $B$ and $C$ using the law of conservation of ...
- 45
0
votes
1
answer
380
views
Gravitational Potential Energy Lab Confusion
I had a lab that tested the dependence of gravitational potential energy on its position and the goal out of each exercise was to see if kinetic energy equaled potential energy. A cart was on a flat ...
3
votes
1
answer
537
views
Doubt in the expression of Lagrangian of a system [duplicate]
There is a problem given in Goldstein's Classical Mechanics Chapter-1 as
20. A particle of mass $\,m\,$ moves in one dimension such that it has the Lagrangian
\begin{equation}
L\boldsymbol{=}\...
- 436
2
votes
2
answers
1k
views
Why can't energy be below the minimum of the potential in a bound state? [duplicate]
I just stumbled across the problem and have no idea how to solve it:
"Considering the Time-Independent Schrodinger Equation for a stationary state $\psi$ with energy $E$, that is $$\psi '' = \...
- 418
1
vote
3
answers
93
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An object which is thrown up rises to a height $h$ and and is stopped at height $h/2$. What is the work done?
So, I had this question in mind for a few days now, suppose an object of mass $m$ is thrown up by a person.
Now, work done on the object would be stored in the form of potential energy, now it rises ...
- 356
0
votes
2
answers
327
views
What is the work done in pushing an object up a slope of mass $m$ to a height $h$?
What would be the work done when an object is pushed up a slope, My teacher recently said that work done on the object would be greater than PE, can someone explain it to me if this is right or ...
- 356
0
votes
1
answer
43
views
Potential energy to gain elevation
I did a calculation to see how high the energy in a cell phone battery could lift an adult assuming perfect efficiency but something seems way off.
...
- 105
1
vote
2
answers
132
views
Understanding kinetic and potential energy
A bullet with mass $8g$ flying at the speed of $v_0=600$ $m/s$ strikes
an apple and comes out at the speed of $500$ $m/s$. Calculate the work
($A$) of the force exerted by the apple on the bullet.
...
- 149
1
vote
1
answer
1k
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Is potential energy always inversely proportional to separation?
This is a question from Class 11 Physics NCERT.
The answer is that only graph (v) is correct and the reason given here is that potential energy varies inversely with separation. But does that always ...
- 83
0
votes
2
answers
3k
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Energy change as ball rolls down a curved ramp [closed]
At the top of the ramp, the ball has gravitational potential energy. As the ball rolls down the ramp, the potential energy converts to kinetic energy. Due to friction, some energy is also converted to ...
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