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    Hi everyone, im fully content with the other two laws, but dont seem to understand the first one properly....how can all the forces on an object be in equilibrium and it still be able to move?... i though when they are in equilibrium it would stand still????

    im not sure if im a total numpty, any helpp????
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    If there's a net force, that is the forces aren't in equilibrium, there must be an acceleration as F=MA.
    However, although there is no net force, and thus no acceleration, this doesn't mean it's not moving. Just that if it is moving, it's at a constant velocity.


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    (Original post by Tomothy)
    If there's a net force, that is the forces aren't in equilibrium, there must be an acceleration as F=MA.
    However, although there is no net force, and thus no acceleration, this doesn't mean it's not moving. Just that if it is moving, it's at a constant velocity.


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    hi there, thanks alot it has sort of cleared it up.... i understand that if there is a net force there is an accelations from F=ma, however i cant get the grasp of something moving if all the forces acting on it are balanced wouldnt it be almost "stuck" as it is getting pushed equally from all sides?... Its just i dont understand how something can be moving (with a constant velocity) if all the forces on it are balanced... sorry for all the hastle
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    (Original post by salaama)
    hi there, thanks alot it has sort of cleared it up.... i understand that if there is a net force there is an accelations from F=ma, however i cant get the grasp of something moving if all the forces acting on it are balanced wouldnt it be almost "stuck" as it is getting pushed equally from all sides?... Its just i dont understand how something can be moving (with a constant velocity) if all the forces on it are balanced... sorry for all the hastle
    It's "stuck" moving. That's the point. Imagine being on an ice rink: assuming it was perfectly slippery, if you push yourself off a wall you will never slow down until something (i.e. a force) stops you.

    If you think about it, motion at a constant speed isn't distinguishable from being stationary at all! In fact, "stationary" doesn't really have any objective meaning - if a car is moving past you at one speed, it is just as accurate to say that you are moving past it at that speed in the opposite direction! The universe and the maths/physics can tell no difference - because there isn't one.
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    (Original post by salaama)
    hi there, thanks alot it has sort of cleared it up.... i understand that if there is a net force there is an accelations from F=ma, however i cant get the grasp of something moving if all the forces acting on it are balanced wouldnt it be almost "stuck" as it is getting pushed equally from all sides?... Its just i dont understand how something can be moving (with a constant velocity) if all the forces on it are balanced... sorry for all the hastle
    Well if you break it apart like this:
    (I hope this works!)

    If we consider one body we know that there is one mass, let's say 20kg

    If we know that F = ma then there are two situations where the forces will be in equilibrium,
    when the body is stationary:

    a = 0ms-2 therefore F = 20kg x 0ms-2 = 0N
    all forces are all equal to 0

    and when the body is moving at a uniform rate, let's say 2ms-2

    So remember we said there is one body, so for that one body all the forces acting on it are travelling with it --> all the forces have an acceleration of 2ms-2

    So for every force F will equal 20kg x 2ms​-2 therefore every force is equal!

    I hope that helped a bit
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    Resultant force causes ACCELERATION/deceleration.

    No resultant forces causes either constant velocity or rest.

    That's all that N1L says really.
 
 
 
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