All Questions
11
questions
2
votes
2
answers
111
views
Why do higher objects have a greater force?
We did an experiment in class today using a spring scale, a plastic bag, and a variety of other objects. Essentially, we attached the bag to the spring scale and measured the force, in newtons, of ...
- 539
-1
votes
2
answers
212
views
Why does GPE convert to kinetic energy? [closed]
What is it about GPE that makes it transfer to kinetic energy, why does it do this? What is GPE?
7
votes
3
answers
1k
views
How is gravitational potential energy $mgh$?
I know the derivation that $W=Fd$, hence $F=mg$ and $d=h$ so energy gained by the body is $mgh$ considering the body on the ground to have $0$ gravitational potential energy.
But the definition of ...
- 1,168
0
votes
3
answers
133
views
Amount of work: clarifications
If to lift an object of mass $m$ a force greater than $mg$ is required then why do we take the amount of work done in lifting an object as $mgh$ could someone please explain that to me?
- 356
1
vote
4
answers
2k
views
How do you calculate the energy required to hold a weight against gravity?
What is the energy required to hold a mass in place? To lift 1kg 1m at sea level I must use 9.8 J. but if I simply grab onto a 1 kg mass that is on a table and the table is removed. I am now using ...
- 161
0
votes
2
answers
1k
views
Why is gravitational potential energy $= mgh$? And how is it useful to us? [closed]
Who introduced the concept of gravitational potential energy?
Why do we need it to describe the physical world and how is it useful to us?
And from where does the formula $ U = mgh$ come from?
- 39
-1
votes
2
answers
292
views
Potential Energy equation is wrong as $mg$ force acting upwards (by us) and gravitational force ($-mg$) get cancelled and no movement is possible [duplicate]
In physics, the potential energy of an object is mgh. We say that the potential energy of an object is equal to the work done on it to make it reach that height. So the work done = mg h. Mg is the ...
5
votes
2
answers
227
views
Positive and Negative works [duplicate]
When we displace a body from ground to a height we do positive work against gravity and gravity too does work but negative. Do they cancel each other? Or does the external force do extra work?
0
votes
1
answer
408
views
Why does the water rise upwards when the bottle fall down with accleretion $>>g$?
When a medium-sized bottle filled with water quarterly falls from a height with acceleration $g$, the water remains calm. But when it falls with acceleration $>>g$, the water abruptly rises up ...
user36790
1
vote
4
answers
692
views
How much up will an object of mass $m$ will be vertically lifted if a constant acceleration $a$ is given so that resulting force is more than weight?
Yesterday My friend asked me a question which put me into a confused state.
If a body of mass m is given a vertical thrust of $F$ such that $F > mg$, and the $F$ is allowed to remain applied on ...
- 51
4
votes
1
answer
515
views
Would the Moon drift away from the Earth due to extraction of tidal energy? [duplicate]
Possible Duplicate:
Why does the moon drift away from earth?
It seems to me that, due to conservation of energy, the moon would drift away from the Earth if humans began extracting large amounts ...
