Dynamics is a branch of classical mechanics, mainly to study the changes in the movement and the factors that cause this change, pure description of the movement of objects, do not take into account the factors that lead to movement. The basic law of dynamics is the Newton law of motion proposed by Isaac Newton: the first law (the law of inertia), the second law (the law of acceleration), the third law (the law of force and reaction), for any physical system, As long as we know the nature of its force, we can study the influence of this force on the physical system by referring to Newton's law of motion.
Long-Lasting Wheels of Wind and Fire
There is a fast rotating disc at the center of the table. Try roll a ball from one end of the table to the other. What rolling track will the ball create? When you place the ball at the center of the disc, as it gradually moves away from the center, what changes will occur to its "orbital" and "spinning" motion? Why? Try and place the discs or rings on the rotating disc. Can you find a method to make these objects spin for a long time? Roll the discs or rings in an opposite direction of the rotating disc. Does this method help?
Moment of Inertia and Rotational Energy
The handles on both sides of the disc can be turned in a reversed direction to adjust the placement of weights, which will alter the mass distribution in the entire disc. Move the weights of one disc to its center, and distribute the weights of another disc to its rim. Release the two discs simultaneously from the top of the slide. Which one will arrive at the end first? Why?
A Sphere, a Disc, and A Ring, which one runs the fastest?
The mass of the ball, disc, and ring is the same. When they are released and rolled down from the same height, which one will arrive at the end first? Why?
Rolling Ball Relay
Line up the magnetic rails in different ways on the wall to form a downward trail. Whose trail can keep the ball rolling for the longest? What energy conversion between two forms of energy does this exhibit show?