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## Newton's first law of motion

For just a moment, let us imagine that you can apply only one force to an object. That is, you could choose push the object to the right or you could choose to push it to the left, but not to the left and right at the same time, and also not up and to the right at the same time, and so on.
Under these conditions the first law says that if an object is not pushed or pulled upon, its velocity will naturally remain constant. This means that if an object is moving along, untouched by a force of any kind, it will continue to move along in a perfectly straight line at a constant speed.

The first law also means that if an object is standing still and is not contacted by any forces, it will continue to remain motionless. Actually, a motionless object is just a special case of an object that is maintaining constant velocity. Its velocity is constantly 0 m/s.