the equation for rotational kinetic energy (KE) is:
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KE = 0.5 * I * ((rad / sec)^2), where I is the mass moment of inertia.
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so if the kinetic energy remains constant, the only thing that can alter the rotation rate (rad / sec), is I, the mass moment of inertia
The reason a skater spins faster when she pulls her arms in is because of angular momentum. It is measured by mass x velocity x radius. Bringing her arms in changes her radius and velocity.
It must spin faster in order to conserve angular momentum ... the same reason that a skater spins faster when he pulls his arms in close to his body.
If you've ever watched an Olympic ice skater do a spin, you may have noticed that he or she will draw in her arms closer to her body in order to increase the speed of rotation. This is in keeping with the law of the conservation of angular momentum.
20kg
Tornadoes owe their extremely fast winds in part to something called the conservation of angular momentum. If something that is rotation contracts in width then the spinning must speed up, such as with a spinning ice skater pulling in her arms. Tornadoes form when a larger but less intense mass of rotating air tightens and intensifies.
The reason a skater spins faster when she pulls her arms in is because of angular momentum. It is measured by mass x velocity x radius. Bringing her arms in changes her radius and velocity.
If the velocity is constant, it follows that the the sum of all forces on the ice skater is zero.
It must spin faster in order to conserve angular momentum ... the same reason that a skater spins faster when he pulls his arms in close to his body.
If you've ever watched an Olympic ice skater do a spin, you may have noticed that he or she will draw in her arms closer to her body in order to increase the speed of rotation. This is in keeping with the law of the conservation of angular momentum.
Acceleration is change in velocity. These are vectors that have magnitude and direction. Changing either magnitude (speed) or direction will have the skater be accelerating. SO, if the skater is going at a constant speed of 2m/s in a straight line, he is not accelerating. If he is at a constant speed of 2m/s traveling in a circle (you gave the word "around"), he is accelerating. Going around in circles means there is a force constantly changing your direction. Obviously that force is coming from the skaters legs.
20kg
The answer is related to the conservation of angular momentum. A figure skater will maintain approximately the same angular momentum during their spin (minus a negligible amount due to the friction of their skates and wind resistance). When they move their arms in, they will reduce their rotational inertia by reducing the distance of the mass of her arms and hands from the axis of rotation. In order to maintain the same angular momentum, angular rotation is increased. See the link. Its called the angular conservation of energy. No matter what the skater's position the skater produces a certain amount of energy per second. When his / her hands are extended the distance of the rotation is larger. When he pulls his hands in the weight is unchanged. TO keep the energy at the same amount the difference has to be made up by increasing the number of spins per time unit.
The radius of her path Her speedHer mass apex
The radius of her path Her speedHer mass apex
By first spinning with the Arms extended, and then bringing the arms close to your body, you will spin faster. This is due to the conservation of angular momentum and energy. The equation for the amount of angular energy is (1/2)(I)(W^2) I is inertia W is angular velocity (pretend the W is lower case omega) When you have your arms and legs out, You have an increased Inertia. According to the conservation of angular energy, your have to have just as much energy starting out as you do in the end. So, when you bring your arms and legs in, you increase your ending omega by decreasing you ending inertia.
She can move her arms inwards - to increase the rotation speed - or outwards - to decrease it.
HE IS A PRO SKATER HE IS A PRO SKATER HE IS A PRO SKATER HE IS A PRO SKATER