When lifting weights, do players need to put some on their hands? Calcium sulfate? Is that what we always say? Magnesium powder? . Calcium sulfate is light and absorbent. During activities, athletes' palms often sweat, which is very unfavorable for gymnasts and weightlifters. Because the wet palm will reduce the sliding friction of the player, so that the equipment can not be held, which not only affects the effect of posture, but also may cause the player to fall off the equipment, causing mistakes and even injuries. Calcium sulfate can not only digest and absorb sweat from palm, but also improve the friction between palm and equipment. Therefore, players can hold the equipment tightly, which is conducive to improving the test scores of fitness exercises. The basic concept of weightlifting is to apply classical mechanics to establish a structural mechanical entity model of leg clamp and pavement. Perspective? For generalized coordinates, consider the symmetrical weight lifting method, assuming that the lifting object increases y 1 and body angle? With what? There is a differential tube bundle correlation in the middle. According to the software dynamic equation of multi-rigid-body system, the hip angle is obtained. The instantaneous velocity curve and the internal force and moment of hip bone are obtained, which is convenient for further discussion and understanding of structural mechanics. The analysis shows that the internal force and moment of hip bone are related to angular acceleration, and it is an ideal weight lifting method to manipulate symmetry as much as possible.
Second: Physical knowledge when running.
Friction: Sprinters should wear a pair of 100-meter running shoes in the whole process of 100-meter running. There are small steel nails at the bottom of these shoes, and the height-width ratio of athletes is high. The running speed is fast, and the small steel nails can be inserted into the sports ground to reasonably avoid the players from falling. Running fast must be determined by the sliding friction between the feet and the road. Jogging with spikes can improve friction. If the sole is slippery, the friction is small, which is not good for jogging.
Inertia: The deeper you run, the faster you run. This is cohesion. After reaching the finish line, it will travel a little further, which is the role of inertial force.
Acceleration: the instantaneous speed increases during the sprint, that is, the sprint is fast.
Inertia force: after running to the finish line, it will go forward again.