1, average speed introduction:
The average speed roughly represents the movement of an object over a period of time. Applied to physics, mathematics and natural science. The average velocity is a vector whose direction is the same as the displacement direction in a period of time t, but not necessarily the same as the movement direction.
The ratio of displacement to time of a variable-speed moving object is not constant. At this time, we can use a speed to roughly describe the moving speed of an object during this time. This speed is called the average speed.
2. Calculation formula:
2×V 1×V2÷(V 1+V2)= average speed. (The average speed in the first half is V 1, and the average speed in the second half is V2).
In uniform linear motion, the average speed can also be calculated by (V0+Vt)÷2, and at this time, the average speed also represents the instantaneous speed in the middle of the time spent through this displacement. However, if it is uniform and variable speed, there is another formula = (initial speed+final speed) /2.
The difference between average speed and average speed:
1, the average speed is not the average speed:
The average speed is the ratio of the distance an object moves to the time it takes to move this distance. It is a scalar. When moving in a straight line in one direction, the average speed is equal to the numerical average speed. )
2, the average speed is the ratio of distance and time:
Proportion cannot be measured, and it is generally not equal to the average speed. For example, if an object moves in a circle, with t, the average speed is 2πr/t and the average speed is 0. Specifically, the average speed refers to the displacement speed of an object in a selected time. For example, after t seconds, the object returns to its original position, so its displacement is zero and its average velocity is zero.
3, the average speed is a vector:
Its direction is the same as the displacement direction in a period of time Δ t, but not necessarily the same as the movement direction. In uniform linear motion, the instantaneous speed at the middle position is greater than the instantaneous speed at the middle moment.
4, in the variable speed linear motion, the size of the average speed is related to the selected time or displacement:
The average speed of different time periods or different displacements is generally different, so it is necessary to specify which time period or displacement the average speed corresponds to, and it is meaningless not to specify the average speed of the corresponding process.