All Questions
7
questions
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
2
votes
2
answers
186
views
Does a magnet lose mass if it’s doing work?
If a standard refrigerator magnet is used to hold up a piece of paper is it doing “work”? If so it would seem to me that energy would be required for that work and then by extension energy would be ...
- 21
3
votes
2
answers
538
views
Does the work-energy theorem assume that the particles of the system have time-independent masses?
$\newcommand{\force}{\mathbf{F}}$
$\newcommand{\velocity}{\mathbf{v}}$
$\newcommand{\position}{\mathbf{r}}$
Here's an incomplete proof of the work-energy theorem:
$$W = \int_1^2\force \cdot d\...
user113773
1
vote
1
answer
346
views
Work-Energy Theorem for Non-Constant Mass
"The net work done on an object is equal to its change in kinetic energy."
Let's say that a rocket is moving upwards while expelling gas and is thus losing mass. (Non-constant mass)
As the object ...
- 395
1
vote
2
answers
840
views
Does distance traveled by a vehicle after its engine has been switched off depend on its mass at all?
A vehicle moving with some velocity on a rough horizontal road finally comes to rest after its engine has been turned off. Intuitively, it seems a vehicle with greater mass would stop first because it ...
- 1,867
0
votes
2
answers
423
views
almost same mass, same distance, different energy needs
Imagine a car, driving 10 km at constant speed in 6th gear. There will be a measurable fuel consumption.
Now imagine the same car driving 10 km again at a constant speed (same as above) in the 1st ...
- 125
1
vote
3
answers
166
views
Carrying water on person, or on the frame when bicycling
So, the question is as follows:
What is the difference in work exerted by the rider in the two following scenarios?
a) Rider + bike. Water carried in a holder on the frame
b) Rider + bike. Water ...
- 11