Relationship between force and motion

Answer 1

An object will only change its motion if undergoing a force acting upon it. An object does not, necessarily, need a force to act upon it to move; it needs only a force to accelerate (or decelerate!)

If dealing with an object at rest, this equation works best to describe how that object can begin to move:

F = ma

Where F is the force applied, m is the mass of the object, and a is the acceleration.

Therefore, if you apply a force of 10 Newtons to a mass of 10 Kilograms constantly, the object will undergo uniform acceleration of 1 m/s^2 -- ie, it will increase its velocity by 1m/s (meter per second) every second.

A force does not need to be constantly applied to an object for it to continue to move. If a force of 10 Newtons is applied to an object of mass 10 kilograms for just one second, the object will accelerate to AND THEN REMAIN AT the velocity 1 meter per second.

Now, if you're dealing with objects already moving, the equation looks a little different: it's called the impulse equation, and it describes the relationship between forces and objects in the context of a CHANGE OF MOTION (or, specifically, momentum.)

It reads as follows:

FT = m(Vf - Vo)

F and m are the same as above.

Essentially, this equation describes the change in motion--starting at "Vo" and ending with "Vf" of an object mass "m" when the force "F" is applied for "T" seconds.

That's really all there is to know--for LINEAR motion, which I assume you're referring. If you mean angular motion, that's another ballgame, and one I really don't want to get involved with ;)