Units of measure in physics play an important role in solving practical problems. Thanks to them, you can determine the correctness of the result and understand its quantitative value in comparison with the well-known standard. Consider in the article what a physical quantity is with a unit of measure newton per meter.
Newton - unit of force
Every student knows who Isaac Newton is and what contribution he made to the development of classical mechanics. With absolute certainty, we can say that dynamics, as a section of physics studying the forces, is completely built on the laws of the great English scientist. Therefore, the international community decided to name the unit of measurement of force as Newton (N). One Newton is such a force, which, acting on a body weighing 1 kilogram, tells it an acceleration of 1 m / s 2 .
Newton is the main unit of measure for absolutely any kind of force. Nevertheless, it is not among the seven basic units of the international SI system. As it was said, it is determined through 3 other basic concepts - kilogram (measure of mass), meter (measure of distance in space) and second (measure of time).
What is newton per meter?
Having become acquainted with the concept of "Newton" as a unit of measurement of forces, we return to the topic of the article. What is the value if you multiply a newton by a meter? For those who cannot immediately answer the question posed, we write this operation in mathematical form:
A = F * l
If, as a result of the action of the force F, the body moves a distance l, then the product of these physical quantities will give the work done by the force along the direction of movement.
Work is an energy characteristic, it is measured in joules (J). One joule, in accordance with the definition of work, is such energy that a force of 1 newton will expend when moving the body 1 meter.
Depending on the physical process, the work spent on moving bodies can turn into various types of energy. For example, if a construction crane lifts a concrete slab, then its potential energy in the field of gravity increases. Another example: people, applying constant force, push the car for some time. Part of the work spent is on overcoming the rolling friction force and, as a result, goes into heat energy, its other part goes on increasing the kinetic energy of the vehicle.
Thus, a newton per meter is a unit of work called the joule.
Moment of power
In addition to the work, the indicated unit is also used to measure the moment of force. The latter is described by the same formula as the work, however, the force in this case is directed at a certain angle to the vector l, which is the distance from the point of application of force to the axis of rotation.
Despite the fact that the moment of force is described in units of work, it is not. It is also called torque, because it shows the possibility of an external force to rotate the system around an axis and give it some angular acceleration. If the moment of force is multiplied by the angle of rotation in radians, then we get the job. The unit of measurement will not change.
Pressure unit
As part of the topic of the article, we also consider how pressure is measured in physics. People who are keen on this science will quickly give the correct answer, naming pascal as a unit for measuring pressure in SI. In tasks and in practice, other pressure units are often found that are convenient to use in each case. So, it is widespread: atmosphere, torr or millimeter of mercury and a bar. Each of them is unambiguously converted into pascals, if we use the corresponding conversion factor.
We consider pressure as part of the topic of this article because it is closely related to power. By definition, pressure is a value equal to the ratio of the force acting perpendicular to the surface surface to the surface area, that is:
P = F / S
From this equality we get the unit of measure Newton per square meter (N / m 2 ). The value of 1 N / m 2 is called Pascal in honor of the French physicist Blaise Pascal, who constructed the barometer and measured atmospheric pressure at different altitudes relative to sea level.
One pascal is a very small pressure. Its value can be imagined if you take 100 milliliters of distilled water and distribute it over an area of 1 square meter. For example, we note that atmospheric pressure at sea level is approximately equal to 100 thousand pascals.
For completeness, we note that the quantities with a newton unit of measure multiplied by a square meter do not exist in physics.
Task example
It is necessary to determine what work gravity did if the body fell from a certain height to the surface of the earth in 5 seconds. Take the mass of the body equal to one kilogram.
Gravity can be calculated by the formula:
F = m * g = 1 * 9.81 = 9.81 N
To determine the height from which the body fell, you should use the formula for uniformly accelerated movement without an initial speed:
h = g * t 2/2 = 9.81 * 5 2/2 = 122.625 m
To get the work of gravity, multiply the values of F and h:
A = F * h = 9.81 * 122.625 ≈ 1203 J
Gravity has done a positive job of approximately 1,200 Newtons per meter, or 1.2 kilojoules.