作者NBASCIDM (战神)
看板NTU-Exam
标题[试题] 97上 黄晖理 普物甲上 第四次小考
时间Wed Dec 24 14:51:09 2008
课程名称︰普通物理(甲)上
课程性质︰大一共同必修
课程教师︰黄晖理
开课学院:生农学院
开课系所︰生物产业机电工程学系
考试日期(年月日)︰12/24/2008
考试时限(分钟):50 minutes
是否需发放奖励金:yes
(如未明确表示,则不予发放)
试题 :
1.A string oscillates according to the equation
Y'=(1cm)sin[(1/3cm^-1)x]cos[(40πs^-1)t]
What are the (a)amplitude and (b)speed of the two waves(identical except for
direction of travel)whose superposition gives this oscillation? (c)what is
the distance between nodes? (d)what is the transverse speed of a partical of
the string at the position x=2cm when t=1s ?
2.Two trains are traveling toward each other at 30m/s relative to the ground.
One train is blowing a whistle at 550Hz.(assume speed of sound in the air is
343m/s)
(a)What frequency is heard on the other train in still air?
(b)What frequency is heard on the other train if the wind is blowing at
30m/s toward the whistle and away from the listener?
(c)What frequency is heard if the wind direction is reversed?
3.At a result of a temperature rise of 35度C,a bar with a crack at its center
buckles upward.If the fixed distance L0 is 3m and the coefficient of linear
expansion of the bar is 25×10^-6/度C,find the rise x of the center.
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