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Relation between velocity and force 
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#1
Oct2608, 06:46 AM

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Ok, so heres the question. To make a car move, we need a force, however, the velocity of the car is related to force? By example, we made a force to make the car start moving and the car started moving with a velocity of 10m/s. Then later the car has a velocity of 20m/s. So, the increase of the velocity is caused by a bigger force pushing the car? Cos, i do know that if the car is moving, then it has the tendence to keep moving with a constant velocity, it can only be stoped with a force in the opposite way to make it stop, so to make it go faster, then theres a force pushing it to go faster?



#2
Oct2608, 06:52 AM

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Welcome to Physics Forums.
I'm not sure that I entirely understand your question, but yes, to change an body's velocity there must be a net force acting on that body. 


#3
Oct2608, 06:55 AM

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ok, and whats the formula to find the force used in the increase of velocity? thanks by the answer gived by the way.



#4
Oct2608, 06:58 AM

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Relation between velocity and force
Er... F=ma!
Zz. 


#5
Oct2608, 06:59 AM

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but thats when a = v^2/r in a circular movement. and on a rectilineous movement?



#6
Oct2608, 07:09 AM

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I just want to make sure that you know that the equation for acceleration that you quoted is only valid for circular motion. 


#7
Oct2608, 07:09 AM

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Since when is F=ma only valid in circular motion? Zz. 


#8
Oct2608, 08:08 AM

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I also want to make sure you understand how Newton's first law applies to a car: the car decelerates when you take your foot off the gas pedal because there are forces acting to decelerate it. And when you add more gas, the car accelerates to a new equilbrium with its opposing forces. Force has no direct relationship with velocity, only acceleration.



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