IIT JEE , AIEEE Forum - Physics , Mechanics

aamil4u

What is potential energy?

What is the physical significance of potential energy?

Why is potential Energy negative?

If a body is attracted towards the earth from infinity, does its potential energy decrease as it moves closer to the earth or increase?

ambareesh13

in simple meaning potential energy is negative of work done but scientific meaning is -ve of line integral of force.....well its significance in "IIT" physics is limited to mainly to that when we do work on a body it gets stored into it as potential energy unless if it isnt loss in some other form like kinetic energy or heat sound etc.......the potential energy increases when the body is brought close to earth from infinite distance because the absolute potential energy is defined as 0 at infinity......and in simpler terms work done is generally positive when you apply force against repulsion because the angle remains acute and work done is negative if you generally apply force against attractive forces.....hope this helps you a bit

rate me for my efforts please

aamil4u

Thank you ambareesh13 for making an attempt I appreciate your efforts and I have also rated you for that

However whatever you have provided here is something I already know
What I really wanted to know is this
We say that Gravitational potential energy is defined as
E=-GMm/R
Where the symbols have their usual meanings

According to this equation, the potential energy should increase as we move towards the earth

But when we calculate potential energy as E=mgh, we say that the energy of the system decreases as we descend towards the earth's surface

Moreover, In Interactive physics Vol 4 [work energy power] it is mentioned on page 41 [ in C 10 ] that positive work done by a conservative force decreases the potential energy of the system

According to this explanation then, the potential energy of a system should decrease as we move towards the earth from infinity

Which explanation is right??

phyana

look this dude.........

potential energy is something defined by us in the way we preffered better.
we say at infinity p.e=0. since there is no gravity.
we defined it as the max potential possiable.once we come towards earth pe decreases.ie it become negative.

if we want to define the pe of anotheer place we find it relative to the earth position.becaz there is no absolute pe.

aamil4u

Thank you Phyana
I have now understood the concept quite well

Ask & Discuss Questions with Community & Experts