- #1
vansh123
- 4
- 0
hey guys i had a doubt can someone please explain me why force=mass x acceleration?
Every body continues in its state of rest or uniform motion in a straight line, except insofar as it doesn't.
The reasoning presented here, viz., that the First and Second Laws are actually definitions and that the Third Law contains the physics, is not the only possible interpretation. Lindsay and Margenau (Li36), for example, present the first two Laws as physical laws and then derive the Third Law as a consequence.
DaleSpam said:Usually Newton's first law is considered to be a definition of inertial frames and Newton's second law is considered to be a definition of forces. Once those terms are defined, then Newton's third law is the one that contains the actual physics.
MikeyW said:I'm sure the answer is that it's an empirical law. If you apply double the force, you observe the object accelerates twice as much. Do this experiment in enough ways and it's soon fairly convincing that F=ma and not m/a or ma^2 or something weird.
Correct, it is not how Newton gave them. It is how modern physicists interpret them with the advantage of several hundred years of hindsight.voko said:This is not how Newton gave them.
Excellent, then it seems we are not at odds.Jolb said:Your view is certainly a valid way of looking at things
Which is why I qualified my statements with the word "usually".Jolb said:but it is not the only possible way.
The problem is: How do we know that we've doubled the force? How else do we measure the force except using [itex]F = kma[/itex] itself? In other words, we're brought back to regarding [itex]F = kma[/itex] as true by definition.MikeyW said:I'm sure the answer is that it's an empirical law. If you apply double the force, you observe the object accelerates twice as much. [... ]
Yes, this is exactly what I meant by "an experimental prototype force".Philip Wood said:For example, if we use two identical, equally stretched springs
vansh123 said:hey guys i had a doubt can someone please explain me why force=mass x acceleration?
Experimental prototypes of force are not nearly as reliable as measurements of acceleration or experimental prototypes of mass. So generally it is preferable to take Newton's 2nd as a definition of force, since you can get more accurate results that way than by using an experimental prototype force. Your rather rude assertions notwithstanding.joeh1971 said:DaleSpam doesn't know what he is talking about. Newton's 2nd law is an empirical relation between force and acceleration, it is not a definition although some people do use it as an operational definition of mass. I can measure force and acceleration seperately and Newton's 2nd law tells me the mathematical connection between the two.
Newton observed, as did Galileo (which is why we refer to the principle as Galilean Relativity), that the laws of physics are the same in a boat moving at constant speed on calm seas as they are on land. In other words, the laws of motion are the same for bodies in all inertial reference frames (frames of reference of a body undergoing no change in motion).vansh123 said:hey guys i had a doubt can someone please explain me why force=mass x acceleration?
The equation f=ma is known as Newton's second law of motion. It states that the force (f) applied to an object is equal to the mass (m) of the object multiplied by its acceleration (a).
F=ma is important because it helps us understand the relationship between force, mass, and acceleration. It is a fundamental equation in physics and is used to explain the motion of objects.
F=ma is used in various real-life situations, such as calculating the force needed to launch a rocket, determining the acceleration of a car, or understanding the impact of gravity on objects.
One example of f=ma in action is when a hockey player hits a puck with their stick. The force applied by the stick (f) is equal to the mass of the puck (m) multiplied by its acceleration (a), causing it to move forward.
The units for f=ma are Newtons (N) for force, kilograms (kg) for mass, and meters per second squared (m/s²) for acceleration.