课程名称︰普通物理学甲上
课程性质︰数学系大一必带
课程教师︰黄晖理
开课学院：理学院
开课系所︰数学系
考试日期（年月日）︰2013/12/17
考试时限（分钟）：60
是否需发放奖励金：是
（如未明确表示，则不予发放）
试题 :
1. A sound source S is stationary, and a detector D is moving toward it from A
at speed v. Then turn right by 90 degree at point B. If the sound intensity
is I , detected frequency is f at A. (40 pt)
0 0
(a) What is the intensity I , I at B and C?
B C
(b) What is the frequency f emitted by S?
S
(c) What is the detected frequency f at C?
C
●
C│
│R
│ 1
●───●──●
S R B R A
1 2
2. A gas sample expands from V to 4V while its pressure decreases from P to
0 0 0
P /4. How much work is done by the gas if its pressure changes with volume
0
via (a) path A, (b) path B, and (c) path C? (30 pt.)
A
P ┌─→─┐
0 │╲ │
↓ ↘B ↓
│C ╲│
P /4 └─→─┘
0
V 4V
0 0
γ
3. For ideal gas in an adiabatic process, we have PV = const. (a) Prove it.
a
And TV = const. (b) Find a? (30 pt.)