Question

Was just wondering, and I thought of this.
An object travelling in space with acceleration=0, which means force=0 according to F=ma.
According to E=.5mv^2 the object has energy because it is travelling at constant speed. Now if we consider the
work done=force X distance moved
and work done can be considered as Energy, we get Energy=force X distance moved.
Energy is not zero even though Force is zero.
I have heard that this is because Newtonian Physics dosen't apply here, but I want a detailed answer.
Pls Help

Answer 1

Einstein found that matter could be CONVERTED to energy and the relationship was E = m c^2. However, it is not trivial to make such conversions, through fission and fusion.

Answer 2

if a body has kinetic energy, it experienced a force at initial .. and amount of kinetic energy equals amplitude of force times distance traveled during the force-body interaction..

Answer 3

@Anas.P
Energy is not the same as work.

Energy is an abstract quantity (which somehow remains conserved in every process).
Work is the transfer of energy from one form (ordered energy) to another form (unordered energy).

And your question is within the domain of Newtonian Physics.

Answer 4

what a thinking
too complicated
but i'll try.

Answer 5

So if object moves a distance of x meters when x is not zero, can we say work is done?
If yes, then non zero work done should have non zero energy, even if we consider them not equal.
And please elaborate @LastDayWork

Answer 6

"...So if object moves a distance of x meters when x is not zero, can we say work is done?..."
No, work is not done (as the abject wasn't under the influence of any force).

Consider it this way - The object had some initial velocity (how? ; we can leave that for now). If it moves a distance of x metres (on its own accord) its kinetic energy remains same (as before)

As work involves transformation of energy; we can say that no work is done.

"...If yes, then non zero work done should have non zero energy, even if we consider them not equal..."
I am not sure what you want to ask here but I think you have a physical interpretation for energy.

Consider reading this whole chapter (if possible) - http://www.feynmanlectures.caltech.edu/I_04.html

Answer 7

For all this doubts.. u need to use the most awesome theorem involving work and energy..

THE MIGHTY WORK ENERGY THEOREM!

Net work done on an object = Change in kinetic Energy

and all your doubts will be cleared!

Answer 8

The change in kinetic energ is zero so there is no work done. It's conservation of engergy at work.

Answer 9

Thanks guys...

Answer 10

work done with respect to the object is zero as its moving in a straight line with constant velocity.
but the energy is not zero,yes of course,it remains constant through out the travel of the object in space till its exhibiting cons.velocity