Trap oneLack of understanding of speed and making mistakes?
FalseThe average velocity is considered to be the average of the velocity
The average velocity is the average speed of an object passing a certain distance, which is numerically equal to the motion of the objectTotal distance withThe object is used on this journeyThe ratio of the total time
For example, if the velocity of an object in the first half of the distance is v1 and the velocity of the second half of the distance is v2, then the average velocity of the object in this part of the distance is:
Instead of the speed average.
Trap twoIs it easy to make mistakes in judging the state of exercise?
Motion and rest are relative, only when a reference object is selected can it be determined whether the object is in motion or at rest. If studiedThe position of the object has changed relative to the selected reference, it isExerciseTarget; If the object under study does not change its position relative to the selected reference, it is stationary.
Trap three: Understanding the physical meaning of S-T and V-T images
There are two kinds of common images in mechanical motion: S-T and V-T images, which can vividly and intuitively reflect the movement of objects, and students should be able to distinguish the differences between S-T and V-T lines, and be proficient in the physical meaning of S-T and V-T lines in images.
Trap fourUnderstanding of errorsError-prone
When measuring various physical quantities,There will always be a difference between the measured value and the real value, that's the error. Errors cannot be eliminated, but can be minimized, the methods to reduce the error are: multiple measurements to average, the selection of more precise measurement tools, improve the measurement method, etc., the measurement error is caused by not complying with the rules of use of the instrument, carelessness when reading, etc., should not occur and can be avoided. Errors are not errors.