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讲座14：摆脱束缚和自由轨道圆轨道的各种形式的能量的速度
Lecture 14: Escape Velocities - Bound and Unbound Orbits - Circular Orbits - Various Forms of Energy - Power |
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| 课程网址: |
http://videolectures.net/mit801f99_lewin_lec14/
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| 主讲教师: |
Walter H. G. Lewin
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| 开课单位: |
麻省理工学院
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| 开课时间: |
2008-10-10
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| 课程语种: |
英语
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| 中文简介: |
** 1。逃逸速度：**逃逸速度是逃避引力所需的最小速度。您可以使用机械能守恒来计算它。 ** 2。圆形轨道：**重力提供轨道卫星所需的向心加速度。如果您知道地球周围卫星圆轨道的半径，则可以计算出轨道速度和轨道周期。围绕地球的航天飞机和月球以及太阳周围的地球都有例子。轨道周期与轨道物体的质量无关。 ** 3。功率：**功率是力对物体起作用的速率。瞬时功率是工作的时间导数。力是作用在物体上的力和物体速度的点积。权力是标量;它可以是正数，负数或零。讨论了自行车骑手的力图。骑手所需的动力与速度的第三个力量成比例。 ** 4。热量和各种形式的能量：**讨论热能，热量和比热。描述了焦耳用于将机械能转换成热能的实验装置。提到了几种热源（包括体热）。计算加热洗澡水的能量。讨论了将能量从一种形式转换为另一种形式，并要求学生将机械功率转换为电能。他会坚持多久？ ** 5。能量转换：**电池将化学能转化为电能。制动电池由硫酸和铜和锌电极构成，以短暂点亮灯。 ** 6。全球能源消耗和来源：**美国约占世界人口的1/30，但却占全球能源消耗的1/5。在数值上考虑收获太阳辐射。讨论核电和公众情绪。我们有能源危机！化石燃料可能在100年内耗尽。核聚变正在探索中。证明了Fiestaware釉中存在放射性铀。 （Lewin教授有一个大型的Fiestaware系列）。
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| 课程简介: |
**1. Escape Velocity:** The escape velocity is the minimum speed required to escape the gravitational pull. You can calculate it using the conservation of mechanical energy. **2. Circular Orbits:** The gravitational force provides the centripetal acceleration required for orbiting satellites. If you know the radius of a circular orbit of a satellite around the Earth, you can calculate the orbital speed and the orbital period. Examples are worked for both the shuttle and the moon around the Earth, and for the Earth around the sun. The orbital period is independent of the mass of the orbiting object. **3. Power:** Power is the rate at which a force does work on an object. Instantaneous power is the time derivative of work. Power is the dot product of the force acting on an object and the velocity of that object. Power is a scalar; it can be positive, negative, or zero. A force diagram for a bicycle rider is discussed. The required power to be delivered by the rider scales with the third power of the speed. **4. Heat and Various Forms of Energy:** Heat energy, calories and specific heat are discussed. Joule's experimental apparatus for converting mechanical energy into heat energy is described. Several sources of heat are mentioned (including body heat). The energy to heat up bath water is calculated. Conversion of energy from one form to another is discussed, and a student is asked to convert mechanical power to electrical power. How long will he last? **5. Energy Conversion:** Batteries convert chemical energy to electricity. A make-shift battery is constructed of sulfuric acid with copper and zinc electrodes to briefly light a lamp. **6. Global Energy Consumption and Sources:** The US has about 1/30 of the world's population but accounts for 1/5 of the global energy consumption. Harvesting solar radiation is numerically considered. Nuclear power is discussed and the public sentiment. We have an Energy Crisis! Fossil fuels could be depleted within 100 years. Nuclear fusion is being explored. The presence of radioactive uranium in Fiestaware glaze is demonstrated. (Professor Lewin has a large Fiestaware collection).
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| 关 键 词: |
逃逸速度; 热量; 能量; 能源转换; 全球能源消费
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| 课程来源: |
视频讲座网
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| 最后编审: |
2020-07-05：liush
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| 阅读次数: |
72
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