Units of measurement in physics play an important role in solving practical problems. Thanks to them, it is possible to determine the correctness of the result obtained and to understand its quantitative value in comparison with a known standard. Let's consider in the article what is a physical quantity with a unit of measure newton per meter.
Newton is a 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 branch of physics that studies forces, is completely built on the laws of the great English scientist. Therefore, the international community decided to call the unit of force the Newton (N). One newton is such a force that, acting on a body weighing 1 kilogram, tells it an acceleration of 1 m/s2.
Newton is the main unit of force of absolutely any kind. However, it is not one of the seven base units of the international SI system. As it wassaid, it is defined through 3 other basic concepts - a kilogram (a measure of mass), a meter (a measure of distance in space) and a second (a measure of time).
What is a newton per meter?
After getting acquainted with the concept of "newton" as a unit of measurement of forces, let's return to the topic of the article. What is the value of a newton multiplied by a meter? For those who cannot immediately answer the question posed, let's write this operation in mathematical form:
A=Fl
If, as a result 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 the energy that a force of 1 newton will expend when moving a body 1 meter.
Depending on the physical process, the work expended on moving bodies can be converted 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 a constant force, push a car for some time. Part of the work expended goes to overcome the rolling friction force and, as a result, goes into thermal energy, the other part goes to increase the kinetic energy of the vehicle.
Thus, a newton per meter is a unit of work called a joule.
Momentstrength
Besides work, this unit is also used to measure moment of force. The latter is described by the same formula as work, however, the force in this case is directed at some angle to the vector l, which is the distance from the point of application of the 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, since it shows the ability 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 work. The unit of measure will not change.
Unit of pressure
As part of the topic of the article, we will also consider how pressure is measured in physics. People who are fond of this science will quickly give the correct answer, naming the pascal as a unit for measuring pressure in SI. In problems and in practice, other units of pressure are often encountered, which are convenient to use in each specific case. So, widespread: atmosphere, torr or millimeter of mercury and bar. Each of them is uniquely translated into pascals, if you use the appropriate conversion factor.
We consider pressure within the scope of this article because it is closely related to force. By definition, pressure is a quantity equal to the ratio of the force acting perpendicular to the surface to the area of this surface, that is:
P=F / S
From this equality we get unitmeasure newton per square meter (N/m2). The value of 1 N/m2is called pascal after the French physicist Blaise Pascal, who designed the barometer and measured atmospheric pressure at different heights relative to sea level.
One pascal is a very small amount of pressure. Its value can be imagined if we take 100 milliliters of distilled water and distribute it over an area of 1 square meter. For example, note that atmospheric pressure at sea level is approximately 100,000 pascals.
For the sake of completeness, we note that quantities with the unit of measure newton multiplied by a square meter do not exist in physics.
Example problem
It is necessary to determine what work was done by gravity if the body fell from a certain height to the earth's surface in 5 seconds. Take the body weight equal to one kilogram.
Gravity can be calculated using the formula:
F=mg=19, 81=9, 81 H
To determine the height from which the body fell, you should use the formula for uniformly accelerated movement without initial speed:
h=gt2 / 2=9.8152 / 2=122.625m
To get the work done by gravity, multiply F and h:
A=Fh=9.81122.625 ≈ 1203 J
Gravity has done positive work of approximately 1200 newtons per meter, or 1.2 kilojoules.
