Kinematics is one of the important branches of mechanics that examines the laws of the movement of bodies in space (dynamics studies the causes of motion). In this article, we consider one of the basic quantities of kinematics, answer the question: " What is the path in physics?"
Concept of the way
What is the path in physics? This value is equal to the length of the segment in space that the studied body has overcome during its movement. To calculate the path, it is necessary to know not only the initial and final position of the body, but also the trajectory of its movement. The question of what the path is in physics can be answered differently. This value is understood to mean the length of the trajectory, that is, an imaginary line along which the body moved.
Different symbols are used to indicate the path. So, if we are talking about one-dimensional movement, then we can use the symbol Ξx, where Ξ means a change in the x coordinate. In addition to this symbol, the letters s, l and h are often used to indicate the quantity in question, the latter two mean length and height, respectively. Thus, in kinematics, the letter s is most often found to indicate a path.
If it is known that the body moves in a straight line in three-dimensional space, and the coordinates of its position are known as the initial (x 0 ; y 0 ; z 0 ) and final (x 1 ; y 1 ; z 1 ), then the path can be determined by the formula:
s = β ((x 1 - x 0 ) 2 + (y 1 - y 0 ) 2 + (z 1 - z 0 ) 2 )
Kinematics formulas
Having considered how the path in physics is designated and what this value represents, we give a couple of kinematics formulas that are used to calculate the studied motion characteristic. These are the following formulas:
s = v Γ t;
s = v 0 Γ t Β± a Γ t 2/2
Here, the first expression corresponds to the situation when the body moves uniformly rectilinearly with speed v over time t. The second expression is valid for uniformly accelerated movement, where the symbols v 0 and a denote the initial speed and acceleration, respectively. The plus sign should be used if the body is accelerating, and the minus sign should be used if it slows down.
Task example
Having examined what the path in physics is, we will solve the following problem. The boat at a speed of 13 km / h moves against the river for 1.5 hours from one point to another. What path does the boat go if the speed of the river is 3 km / h?
This is the classic problem of applying the formula for uniform body movement. The challenge is only to determine the actual speed of the boat. Since its movement occurs against the current, it will be equal to the difference: 13 - 3 = 10 km / h. Now it remains to substitute the known values ββin the formula for s and get the answer:
s = v Γ t = 10 [km / h] Γ 1.5 [h] = 15 km
In tasks for calculating the path, it is necessary to monitor the dimensions of the used values ββof speed, time and acceleration in order to prevent errors.