SAT2物理常用术语词汇（H）

　　为了方便广大考生更好的复习，小编综合整理了SAT2物理常用术语词汇，以供各位考生考试复习参考,希望对考生复习有所帮助。>>免费申请出国留学<<

　　Half-life

　　The amount of time it takes for one-half of a radioactive sample to decay.

　　Harmonic series

　　The series of standing waves supported by a string with both ends tied down. The first member of the series, called the fundamental, has two nodes at the ends and one anti-node in the middle. The higher harmonics are generated by placing an integral number of nodes at even intervals over the length of the string. The harmonic series is very important in music.

　　Heat

　　A transfer of thermal energy. We don’t speak about systems “having” heat, but about their “transferring” heat, much in the way that dynamical systems don’t “have” work, but rather “do” work.

　　Heat engine

　　A machine that operates by taking heat from a hot place, doing some work with that heat, and then exhausting the rest of the heat into a cool place. The internal combustion engine of a car is an example of a heat engine.

　　Heat transfer

　　A transfer of thermal energy from one system to another.

　　Hertz (Hz)

　　The units of frequency, dined as inverse-seconds (1 Hz = 1 s–1). “Hertz” can be used interchangeably with “cycles per second.”

　　Hooke’s Law

　　For an oscillating spring, the restoring force exerted by the spring is directly proportional to the displacement. That is, the more the spring is displaced, the stronger the force that will pull toward the equilibrium position. This law is expressed mathematically as F = –kx, where F is the restoring force and x is the displacement. The constant of proportionality, –k, is the spring constant.

　　Hypotenuse

　　The longest side of a right triangle, opposite to the right angle.

　　小编提醒：单词的记忆要靠长期的坚持，考生们一定要持之以恒，每天都拿出来看一看背一背，让这些词汇在大脑中形成长期记忆，这样就不会轻易地忘记背过的词汇了。