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litaa_95
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So, since the Newtons cradle is all about the conservation of momentum. I was wondering, when one ball is released from one side at a certain velocity, why doesn't two balls at the end swing, at half the original speed?
Physics behind Newton's Cradle
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In summary: The steel balls used in the Newtons Cradle are efficiently elastic, meaning they do not lose a lot of energy as heat. This allows for most of the energy to be conserved. If a different, non-elastic material was used, this would not be the case. This also explains why the other four balls could not move with a velocity of V/2. In this scenario, both sides would have equal kinetic energy, thereby conserving the energy in the system. Additionally, it is mentioned that the momentum is not conserved in this case. The
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It's not just conservation of momentum. Most of the energy is conserved too. Two balls at half the speed would only be half the energy.
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Infinitum
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The usual steel balls used in the Newtons Cradle are efficiently elastic, meaning they don't lose a lot of energy as heat. This implies most of the energy is conserved. If some other non-elastic material was used, this wouldn't be the case.
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litaa_95
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why would two balls be only half the energy?
- #5
Infinitum
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litaa_95 said:
Say the initial single ball of mass m has velocity V, and the two balls each(of mass m) have velocity V/2. Can you find out their kinetic energies and co-relate them?
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fermat007
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Then why couldn't the other 4 balls move with velocity V/2? In this case both sides have equal kinetic energy, thereby conserving the energy in the system.
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Infinitum
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fermat007 said:
The momentum isn't conserved in this case
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rcgldr
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Link to article with good explanation of Neton's cradle:
http://www.lhup.edu/~dsimanek/scenario/cradle.htm
http://www.lhup.edu/~dsimanek/scenario/cradle.htm
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davenn
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rcgldr said:
Thats brilliant
thanks for the link :)
Dave
1. How does Newton's Cradle demonstrate the laws of motion?
Newton's Cradle demonstrates the law of conservation of momentum and the law of conservation of energy. When one ball at the end is lifted and released, it gains potential energy. As it falls, this potential energy is converted into kinetic energy, causing the ball to swing and hit the other balls. This kinetic energy is then transferred from one ball to the next, demonstrating the law of conservation of energy. Additionally, the balls that are hit and move are demonstrating the law of conservation of momentum, as they are transferring their momentum to the next ball in the chain.
2. How does the number of balls in Newton's Cradle affect its behavior?
The number of balls in Newton's Cradle does not affect its behavior. As long as there are an odd number of balls, the same principles of conservation of momentum and energy will apply. However, having more balls in the chain may cause the transfer of energy and momentum to be less noticeable due to the smaller movement of each individual ball.
3. Why does the last ball in Newton's Cradle not move as far as the first ball?
The last ball in Newton's Cradle does not move as far as the first ball due to the principle of conservation of energy. As the balls hit each other, some energy is lost through sound and heat. Therefore, the last ball in the chain has less energy to transfer and will not swing as far as the first ball.
4. Can Newton's Cradle be used to generate perpetual motion?
No, Newton's Cradle cannot be used to generate perpetual motion. While it may seem like the balls are continuously moving, they are actually just transferring energy and momentum from one ball to the next. In order to generate perpetual motion, energy would have to be constantly added to the system, which is not the case with Newton's Cradle.
5. How does the height from which the first ball is dropped affect the behavior of Newton's Cradle?
The height from which the first ball is dropped does not significantly affect the behavior of Newton's Cradle. As long as the ball is lifted to a sufficient height for gravity to give it potential energy, the same principles of conservation of energy and momentum will apply. However, dropping the ball from a greater height may result in a slightly more noticeable transfer of energy and momentum due to the increased velocity of the first ball.
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