Does Pushing an Object in Space Result in Infinite Kinetic Energy?

[ofir]

By Newton's second law of motion - inetia,we know that if we push a body in space it will keep moving forever (if nothing stops it) (am I wrong?) but when I think about conservation of energy law I am starting to have problems- let's say that I pushed a body in space,the energy converted into kinetic energy and the body stats moving..i know that nothing stops it but how the energy that I invenst converted to kind of infinity kinetic energy?
hlp?

 

[Drakkith]

That's right. Unless some other force stops it, the object will continue to move forever. The kinetic energy it has is finite though, not infinite, so whether you stop it now or in 10 billion years it will possesses the same amount of kinetic energy. There's nothing strange about this, it's simply the fact that you need to apply a force to stop something. If we say that we will never apply a force, then the object will continue on forever. (Though that's completely non-realistic of course, as gravity has an infinite range and will constantly act on it)

 

[anorlunda]

It sounds like you believe that it requires energy for a body in space to keep moving. That is incorrect. No energy is needed.

On earth, things like cars do need energy to keep moving because of friction, but in an ideal space vacuum, there is no friction.


Newton's first law of motion says, "When viewed in an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external force."

 

[twoslit]

When you pushed it, you gave it a finite amount of kinetic energy. It still has that energy later (assuming nothing else happens to it), and it will have it as long as it keeps moving. This energy lasts as long as the body is moving, but it does not increase. It is the same amount of energy as it was when you had just pushed it. Infinitely lasting is not the same as infinite amount :-)

 

[PJC01]

Hello,

Thank you for reaching out for help with understanding inertia in space. You are correct in your understanding of Newton's second law of motion, which states that an object will continue in its state of motion unless acted upon by an external force. This means that if you push a body in space, it will continue to move forever in that direction, unless something else (like gravity or a collision) changes its path.

However, your concern about conservation of energy is valid. According to the law of conservation of energy, energy cannot be created or destroyed, only transferred or converted from one form to another. In the scenario you described, the initial push you gave the body would indeed convert into kinetic energy, but as the body continues to move, it will encounter resistance from things like gravity, air resistance, and collisions with other objects. This resistance will gradually slow the body down and convert its kinetic energy into other forms of energy (such as heat or sound). Eventually, the body will come to a stop, at which point all of its kinetic energy will have been converted into other forms.

So while it may seem like the body will have infinite kinetic energy, this is not the case. The energy will eventually be converted and dissipated, in accordance with the law of conservation of energy.

I hope this helps to clarify your understanding of inertia and energy in space. If you have any further questions, please don't hesitate to ask. Keep exploring and learning about the amazing world of science!