أكاديميا - كولنز - معاجم الجيب العلمية - الفيزياء - انكليزي - فرنسي - عربي الحرف ٦_ e

Academia - Collins - Pocket Scientific Dictionaries - Physics - English - French - Arabic Letter 6_ E


equations of motion
Equations fpl du mouvement


Equations of motion. These equations determine the uniform acceleration of a body moving in a straight line over a certain period of time and its displacement, the time taken t and its speed 0 and 7, at the beginning and end of the time period.

Each of the five equations determines all of these measures except one. Thus, when we have three equations, we can always find any of the other two equations.

(a omitted) s = 1/2 (u + v) t
(7 deleted) s = ut + 1/2 at2
( u omitted ) s = vt - 1/2 at2
(s omitted) v = u + at
(t omitted) v2 = u2 + 2as

These equations come from the speed/time statement that describes this movement.

The first three equations show that the distance traveled is given by the area under the graph (shaded).


balance
equilibre m

balance . Equilibrium A body is in a state of equilibrium if its momentum (or momentum) is constant, and this is only true when:

There is no resulting force.
There is no resulting bending force.
Here we list some special cases:

A) External forces act along one line. And a total. + F3 One side is equal to the other: F1 = F2.

b) The external forces are parallel, but they do not act in a single line. Here too, the sum of one side is equal to the other side: F + 2 =. The torques are also equal so that the body cannot rotate: F252 = F3S3 F₁.

C) External forces act through one point. Here the triangle of forces applies. (vectors)

See also stability.

“The equilibrant is a unilateral force capable of balancing the active forces, and therefore it is equal to and opposite to the resultant of these forces.


errors
erreurs fpl

mistakes . The reasons that lead to the measured value differing from the true value. To find accuracy of the measured value, one must be able to form some idea of ​​the errors committed. There are three types of errors:

Random errors cause the measured values ​​in a given case to scatter around a given mean. If the errors are random, the average value is very close to the true value. See drawing (a) below.

The real value
8 readings show random errors
Average-----real value
8 values ​​show system errors and random errors

System errors throw all readings away from the true value, as in (b). Some of the causes of these errors are due to a bad suspension of the gauge needle, or to the device not reading zero when it should, or to an error in drawing the chart.

The third type of error results from the physical impossibility of measuring a correct value. Thus, noise in the circuit prevents correct measurement of current. The principle of uncertainty explains that accuracy has fundamental limits in any measurement.


escape velocity (speed)
vitese f d'échapement

Escape velocity is the speed of a body leaving the surface of a planet, for example, when it escapes the gravitational pull. This speed relative to the Earth is 11 kilometers per second.