example of 2nd law of motion?

Answer 1

Newton's second law: historical development
Lex II: Mutationem motus proportionalem esse vi motrici impressae, et fieri secundum lineam rectam qua vis illa imprimitur.

The rate of change of momentum of a body is proportional to the resultant force acting on the body and is in the same direction.

In an exact original 1792 translation (from Latin) Newton's Second Law of Motion reads:

LAW II: The alteration of motion is ever proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed. — If a force generates a motion, a double force will generate double the motion, a triple force triple the motion, whether that force be impressed altogether and at once, or gradually and successively. And this motion (being always directed the same way with the generating force), if the body moved before, is added to or subtracted from the former motion, according as they directly conspire with or are directly contrary to each other; or obliquely joined, when they are oblique, so as to produce a new motion compounded from the determination of both.

Here Newton is saying that the rate of change in the momentum of an object is directly proportional to the amount of force exerted upon the object. He also states that the change in direction of momentum is determined by the angle from which the force is applied.

However, it must be remembered that for Newton, mass was constant and independent of velocity. To take "motion" (motu) as meaning momentum gives a false impression of what Newton believed. Since he took mass as constant (part of the constant of proportionality) it can, in modern notation, be taken to the left of the derivative as . If is dependent on velocity (and thus indirectly upon time) as we would now hold, then has to be included in the derivative, giving or .

Using momentum in the terminology (which would never have occurred to Newton) is a latter-day revision of the law to bring it into correspondence with special relativity.

Interestingly, Newton is restating in his further explanation another prior idea of Galileo, what we call today the Galilean transformation or the addition of velocities.

An interesting fact when studying Newton's Laws of Motion from the Principia is that Newton himself does not explicitly write formulae for his laws which was common in scientific writings of that time period. In fact, it is today commonly added when stating Newton's second law that Newton has said, "and inversely proportional to the mass of the object." This however is not found in Newton's second law as directly translated above. In fact, the idea of mass is not introduced until the third law.

In mathematical terms, the differential equation can be written as:


where is force, is mass, is velocity, is time and is the constant of proportionality. The product of the mass and velocity is the momentum of the object.

If mass of an object in question is known to be constant and using the definition of acceleration, this differential equation can be rewritten as:


where is the acceleration.

Using only SI Units for the definition of Newton, the constant of proportionality is unity (1). Hence:


However, it has been a common convention to describe Newton's second law in the mathematical formula where is Force, is acceleration and is mass. This is actually a combination of laws two and three of Newton expressed in a very useful form. This formula in this form did not even begin to be used until the 18th century, after Newton's death, but it is implicit in his laws.

The laws of conservation of momentum, energy, and angular momentum are of more general validity than Newton's laws, since they apply to both light and matter, and to both classical and non-classical physics.

Because force is the time derivative of momentum, the concept of force is redundant and subordinate to the conservation of momentum, and is not used in fundamental theories (e.g. quantum mechanics, quantum electrodynamics, general relativity, etc.). The standard model explains in detail how the three fundamental forces known as gauge forces originate out of exchange by virtual particles. Other forces such as gravity and fermionic degeneracy pressure arise from conditions in the equations of motion in the underlying theories.

Newton stated the third law within a world-view that assumed instantaneous action at a distance between material particles. However, he was prepared for philosophical criticism of this action at a distance, and it was in this context that he stated the famous phrase "I frame no hypotheses". In modern physics, action at a distance has been completely eliminated. For example, the electrons in the antenna of a radio transmitter do not necessarily act directly on the electrons in the receiver's antenna. According to an everyday timelike observer, momentum is handed off from the transmitter's electrons to the radio wave, and then to the receiver's electrons, and the whole process takes time. If the radio wave itself were to carry a stopwatch and a meterstick and find how long it takes for the momentum to be transferred and whether there is space between the two electrons, then from that perspective the transmitting electron acts directly and instantly on the receiving electron. Conservation of momentum is satisfied at all times and Newton's laws are applicable: for example, the second law does apply to the radio wave (see radiation pressure, radiation reaction force, etc.). Its applicability is guaranteed by accounting for radiowave momentum (see momentum of electromagnetic wave).

Conservation of energy was discovered nearly two centuries after Newton's lifetime, the long delay occurring because of the difficulty in understanding the role of microscopic and invisible forms of energy such as heat and infra-red light.

Newton's Laws






If a bowling ball and a soccer ball were both dropped at the same time from the roof of a tall building, which would hit the ground with a greater force? Common sense tells us that the bowling ball would. We know that gravity accelerates all objects at the same rate, so both balls would hit the ground at the same time. Therefore the difference in forces would be caused by the different masses of the balls. Newton stated this relationship in his second law, the force of an object is equal to its mass times its acceleration. A karate master can exert a tremendous force by utilizing years of training, proper technique and focus. Although a human hand and forearm may have a mass of .75 kg, with proper technique, a karate sensei (master) will be able to use his entire body's mass in breaking bricks. Combining a possible mass of 70 kg and a acceleration of 50 m/s2, this master will exert 3500 N of force, well more force needed to break several bricks. Identify other occurances where Newton's 2nd Law may apply.

Answer 2

A body experiencing a force F experiences an acceleration a related to F by F = ma, where m is the mass of the body. It might be easier to show a larger mass accelerates more slowly with an equal force. This is pretty easy to show in a real life experiment. For your constant force, use a weight tied to a string. The other end of the string is tied to the car. Push the weight off the edge of a table. A light car should accelerate faster, so cover a given distance in less time than a heavier car.

Answer 3

Newton's second law of motion is typically stated F = ma. An example would be that I double the force with which I push a crate across a frictionless floor, and its rate of acceleration also doubles.

Answer 4

The acceleration of an object is directly proportional to the force applied to that object, in the direction of the force.

Answer 5

it is easier to put a ball into motion or stop it than a truck. cos its mass

Answer 6

your penis if pushed into vagina