how on striking the floor kinetic energy =potential energy ........help mate its urgent
Answers
Answer:
Amazing ! and I'm glad you've asked this question.
Mind you this is an absolutely amazing equation and it's not very easy intuitively to just write that equation up
Well, the equation that has been written down there is just a consequence of what we say as the conservation of mechanical energy of any object in Newtonian Or Classical Mechanics.
Now, let's come to the point.
Well, any body has got either Kinetic Energy , Potential energy at any point in same at any instant.
Well, the conservation of energy is just that The total energy of a body remains constant at any point provided that only Conservative forces are acting on the object.
I won't go into deeper details, but you can surely read what would happen if there are going to be non Conservative forces acting on the object too and also that what would the consequences on the equation of conservation of mechanical energy be.
Well, now we can write down
Mechanical energy = Kinetic energy + Potential energy + Internal energy of the object.
Mind you internal energy of an object is the intrinsic property which only changes if you have a significant temperature difference between the two points of analysis.Since the Internal energy is only a function of temperature until now.
However in classical mechanics we don't consider the effect of temperature difference and hence while we equate the sum of energies at point 1 and point 2, the internal energy cancels up being equal in magntiude.
Now,
Since , the energy must be equal at every point
Mechanical energy at point 1 = Mechanical energy at point 2
Here, on analysing
we see that
Kinetic energy of the ball when it is at the top was zero since it's speed was zero as it was at rest.
And it's potential energy was just due to gravity which is given by mgh if Weight = mg and the height is "h".
Now, as it reaches the ground potential energy will be zero since in the problem we consider our reference line to be ground where the potential zero must be taken as absolute zero.
Unlike what we do in Gravitation and Langrangian Formalism.
Maybe I'm going too Deep at the moment.
Alright now let's assume that speed of the ball as it reaches the ground is "v"
So, Kinetic energy of the ball will be given as 1/2mv^2 by definition
and hence by law of conservation of mechanical energy
mgh + 0 = 1/2mv^2 + 0
Giving us
mgh = 1/2mv^2 !
Hurray ! I hope now you got it that from where has that equation been written down.
Hope this helps you !
All the best !