A reference frame consists(1)a coordinate system and(2)a set of synchronized clocks distributed throughout the coordinate grid and rest with respect to it
The Simple Pendulum A pendulum is made by suspending a mass m at the end of a string of length L Find the frequency of oscillation for small displacements mg
The causes of acceleration of a system--The first law of motion states that zero total force exists when the system has a constant velocity; a nonzero total force on the system causes its acceleration
Forces on a Wire Carrying a Current in a Magnetic Field Magnetic Pressure Magnetic Energy Denisity Magnetic Forces btwn Two Electric Currents Magnetic Forces Within an Isolated Circuit
I．Choose the Correct Answer 1. A disturbance can be written x b xt b t a y(x,t) (e e e ) 2 2 −( / ) 2 / − = . This disturbance is （ D ） (A) Not a traveling wave. (B) A traveling wave with speed v = a. (C) A traveling wave with speed v = a/b. (D) A traveling wave with speed v = b
I. Choose the Correct Answer 1. A particle on a spring executes simple harmonic motion. If the mass of the particle and the amplitude are both doubled then the period of oscillation will change by a factor of
I. Choose the Correct Answer 1. Which statement is most correct? (C) (A)Uniform circular motion causes a constant force toward the center. (B)Uniform circular motion is caused by a constant force toward the center
Object: to describe the fieds generated by electric charges and currents Mathematical tools A field is a function describing a quantity at all points in space
由于晶格具有周期性，一些物理量具有周期性，如势能函数： ( ) ( ) 1 1 2 2 3a3 V x V x l a l a l K K G G G = + + + —— 如图 XCH_001_024 所示，A 和 A’两点势能相同。 —— 势能函数是以 1 2 3 a , a , a G G G 为周期的三维周期函数 引入倒格子，可以将三维周期性函数展开为傅里叶级数
