What is the first law?

Question

Christopher Atkinson · Answer

Issac Newton noticed and was able to show, at the macroscopic levels able to be studied at the time, that objects remain in the same state of motion - UNLESS a resultant force acts upon it. So if there sum of the resultant force is zero, then:a stationary ("resting") object remains stationary (at "rest") An object in motion continues to move at the same velocity (It will keep moving at the same speed in the same direction).However, when the sum resultant force on an object is NOT zero, then the object's state of motion will change. It will change velocity. This means it will change speed or direction or speed and direction. In other words, "the object will accelerate".It is important to understand that the word "accelerate" in physics doesn't just mean "speed up".  It means "change velocity".  Velocity is a vector. Velocity has both speed AND direction.  For example, if something is travelling due North at 10ms-1 and is then forced to change direction, say to due East, yet is still travelling at 10ms-, 1 then it still has changed velocity, even though the speed in the new direction is the same speed as the speed in the old direction. The object is still said to have "accelerated". (I've found that that this vectorised notion of "acceleration" is often new to students who may struggle with physics and so the terminology can take a little getting used to, at first)

Sarah Navin · Answer

Essentially Newtons first law states that an object will keep doing what it was already doing as long as no new force is applied to it.So it if was moving East at 10m/s then it will keep moving East at 10m/s. It's velocity (speed and direction) remains the same.If it wasn't moving at all (stationary) then it will remain stationary. Same as above - it's velocity (even though its not moving at all) remains the same.Once a new force is introduced the resultant force (the force that tells you the direction and by how much) will no longer be zero, so the object will either change the speed or direction it's moving in or start to move if it was stationary.

Sharanjit Shokar · Answer

Newtons First law states that an object will remain stationary/at constant velocity, unless there is a resultant force.

James Hilder · Answer

Object at rest or moving with constant velocity remains so unless a net/resultant external force acts

What is the first law?

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