All Questions
12
questions
1
vote
4
answers
673
views
How does mass relate to kinetic energy?
I was working on homework and I had to list what kinetic energy depends on. Interestingly, it turns out it's also based on mass, not only speed. Does anyone have an explanation?
- 539
0
votes
2
answers
71
views
Confusion in calculation of power [duplicate]
Question-
Sand is being dropped from a stationary dropper at a rate of 0.5 kg s$^{-1}$ on a conveyor belt moving with a velocity of 5 ms¹. The power needed to keep belt moving with the same velocity ...
- 252
2
votes
1
answer
43
views
Change of velocity without doing work
Body of mass $1\rm\, kg$ is moving towards left side at velocity of $-2\rm\,m/s$ and is slowing down due to the constant external force until it stops. After that, it's speeding up towards the right ...
- 25
0
votes
1
answer
52
views
Kinetic energy with respect to center of mass frame (COM) [closed]
Let there be an object having some chemicals in it. It starts moving with a uniform velocity $v$ and a chemical reaction starts happening. In this case, which of the following statement/s is/are ...
- 446
1
vote
1
answer
2k
views
How much vertical weight/height do I need to store 33 kWh of energy? [closed]
My question is the feasibility of a vertical mechanical weight battery, but unlike previous questions, I wanted to give a precise scenario and see if my math is right (which I doubt)
First, it takes 1....
- 21
4
votes
2
answers
632
views
Is the change in Kinetic Energy not equal to the work done when mass changes at some rate?
Here the Rate of change in Kinetic energy is not equal to the the power. Please explain
3
votes
1
answer
617
views
The 1-dimensional Kronig-Penney Model: Trying to understand the relation between hopping energy and effective mass
The 1-dimensional Kronig-Penney Model predicts a relationship between energy, $E$ and
wavenumber, $k$ of the form:
$$\cos(ka)=\cos(qa) - \frac{m_e\,A\,t_0\,\sin(qa)}{\hbar^2\,qa}$$
where $$q=\sqrt{\...
- 295
0
votes
1
answer
107
views
Minimum energy of proton converting into a neutron
I'm given the isotope sodium 22 (which is positron emitter) and I'm stuck with calculating the minimum energy that a proton needs to convert into a neutron and a positron.
It got to do with $E=MC^2$ ...
- 1
0
votes
3
answers
110
views
How are these two definitions of energy related/derive from each other? [closed]
How are these two definitions of energy related/derive from each other:
$$E = \frac{mc^2} {\sqrt{(1 - v^2/c^2)}}$$
vs.
$$E = \sqrt{m^2c^4 + p^2c^2}~?$$
Both equations express the relation between ...
2
votes
2
answers
1k
views
Rest mass of the nucleus and its constituent nucleons
One of the question in my book says that if $E$ denote the rest mass energy of a nucleus and $n$ a neutron then,
a.) $E(U^{236}_{92})>E(I^{137}_{53})+E(Y^{97}_{39})+2E(n)$
b.)$E(U^{236}_{92})<...
- 366
0
votes
1
answer
68k
views
How to calculate KE using only mass and height [closed]
For our physics (high school level) group project, we were asked to modify a selected toy so that it produces an energy output of at least or roughly 110% (10% more) compared to the original toy.
Our ...
0
votes
2
answers
156
views
Conservation of Mass, Momentum and Energy - Airburst Rounds
I have a airburst round with set amount of fragments with a certain shape inside my bullet. After a certain distance has travelled, a charge explodes in the back of the round disintegrating the shell ...
- 231