I think that by "Classical physics" is meant low speed things. By low speed, I think is meant speed far below very roughly half the speed of light, so that Relativistic, special or general, effects can be ignored. Or at least it is hoped that they can be ignored.
Fire extinguishers and rockets get propelled by forcing out large amounts of material (gases under very high pressure) through a nozzle, and the RECOIL from that propels something forward. So, if the action is the ejection of material, the reaction (recoil) is the ejector moving along the same line in the other direction. And that's an example of Newton's third law.
Given a propulsion system, the magnitude of the force recoiling on the ejector will change the momentum of the ejector, often written as the equation F=ma where F is the force, m is the mass being accelerated, and a being the acceleration.
Just as something will stay still until it is moved - inertia - so once set in uniform motion in a straight line, the thing will continue in that motion, theoretically for ever or until something alters its momentum. Newton's first law is to the effect of "every body continues in a state of rest or uniform motion in a straight line unless acted on by a resultant external force". Which, I think, is where the concept of inertia stems from.
I think that the above mostly tcuches on the 3 laws.Any more help needed, please ask.
Hi there!
Recall the equation for centripetal force:
We can rearrange the equation to solve for 'r'.
Multiply both sides by r:
Divide both sides by Fc:
In kynematics you describe the motion of particles using vectors and their change in time. You define a position vector r for a particle, and then define velocity v and acceleration a as
In dynamics Newton's laws predict the acceleration for a given force. Knowing the acceleration, and the kynematical relations defines above, you can solve for the position as a function of time: r(t)
