Basic Physics Concept Questions!!

[johnwandering]

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Is Kinetic energy a force?? (probably not)
How can I equate them so that I can relate velocity to force?


What Exactly is momentum? (please describe with a real world scope of view and not math... if possible...)

 

[Enoko]

Force = mass x acceleration

Kinetic energy = 1/2 mass x velocity^2

so to convert force to kinetic energy you need: time, a mass, and the initial velocity. This will allow you to calculate acceleration and final velocity. Now you can find kinetic energy.

As for momentum, compare a slow moving bowling ball, a fast moving bowling ball, and a moving ping pong ball. How would it feel to stop each one with your foot? Faster and heavier gives more momentum

 

[CardiacArrest]

Kinetic Energy isn't a force itself, but it is related to force.

so work = force x distance.
force = m x a (change in velocity/time)
work = change in kinetic energy
so kinetic energy = force x distance.

when an external force is applied, a change in kinetic energy will be experienced. basically, if an external force is applied, an object will experience acceleration. and acceleration is a change in velocity in either direction or magnitude. thus, if there is a change in velocity due to an external force, according to the Kinetic Energy equation, 1/2mv^2, there will be a change in Kinetic Energy.

So it's not a force itself; KE describes the energy change by the system due to the force.


Now for Momentum:
momentum is the tendency for an object to remain in motion. an object with greater momentum will require a greater external force to bring it to a stop. Think of a football game. You have two offensive players. They're both running at the same speed, but player A weighs 100kg, while player B weighs 150kg. It will take much more effort to tackle player B and bring him down, because he has greater momentum.

Hope this helps!!

 

[johnwandering]

Wow, thanks a million

I know that u noted that "Change in KE"=W
But then u also noted that Force x distance = KE
that is also the equation for W

Does this mean that KE=W??

doesn't sound right



sorry, I'm very bad at physics...

 

[Danlee07]

THE CHANGE in kinetic energy

pretty important; not just the initial or final... change

 

[CardiacArrest]

That's the work-energy theorem. It states that any work done on an object is equal to the CHANGE in kinetic energy. This is also applied to electrostatics, btw.
A particle at rest is accelerated to point X. The work done to bring that particle to point X is equal to the change in kinetic energy, which is basically the final velocity - initial velocity.

Applying this to force x distance. An external force will be needed to bring a positive particle close enough to another positive particle.

Ya?? 🙂