Tagged Questions
3
votes
6answers
336 views
Electrostatic Potential Energy Derivation
How is the boxed step , physically as well as mathematically justified and correct ?
Source:Wiki http://en.wikipedia.org/wiki/Electric_potential_energy
As work done = $- \Delta U $. for Conservative ...
2
votes
1answer
142 views
How to understand the work-energy theorem?
How to understand the work-energy theorem?
I took a short lecture on physics for engineering last week. The lecturer emphasized that the work done on an object will cause the kinetic energy change as ...
1
vote
2answers
140 views
Finding maximum speed in a work-energy problem
I have the following problem:
The Royal Gorge bridge over the Arkansas River is $310\text{ m}$ above
the river. A $57\text{ kg}$ bungee jumper has an elastic cord with an
unstressed length of ...
7
votes
3answers
546 views
Is the normal force a conservative force?
Most of the time the normal force doesn't do any work because it's perpendicular to the direction of motion but if it does do work, would it be conservative or non-conservative?
For example, consider ...
2
votes
5answers
267 views
Is there a mathematical derivation of potential energy that is *not* rooted in the conservation of energy?
For simplicity I'll consider only gravity, but in general this question only applies to conservative forces.
As per my understanding, the way one gets to the equation for gravitational potential ...
0
votes
0answers
79 views
How can I measure the calories consumed in daily activity? [closed]
From a nice question here:
How are the calories in food calculated?
I can roughly understand how people provide the data of calories in certain food.
However, I am still confused about 2 things.
1) ...
2
votes
1answer
123 views
Understanding Work and the conservation of energy
We have a car with a mass of $780 kg$ with travels with a speed of $50 km/h$. The car brakes and after $4,2m$ is stops completely. Warmth is created. Calculate the friction.
I solved this easily, by ...
3
votes
2answers
177 views
When work is performed solely by magnetism, is there an equivalent loss of energy from the magnetic field?
When two magnets are placed within appropriate proximity and released, the attractive force will perform work and bring them together. Work is performed overcoming friction. Can we measure a ...
2
votes
4answers
604 views
Work done by the Magnetic Force
The magnetic part of the Lorentz force acts perpendicular to the charge's velocity, and consequently does zero work on it. Can we extrapolate this statement to say that such a nature of the force ...
