Air is flowing through a rocket nozzle. Inside the rocket the air has a density of 5.25 kg/m cubed and a speed of 1.20 m/s. The interior diameter of the rocket is 15.0 cm. At the nozzle exit, the diameter is 2.50 cm and the density is 1.29 kg/m cubed. What is the speed of the air when it leaves the nozzle?
a. 176 m/s
b. 29.3 m/s
c. 35.2 m/s
d. 343 m/s
The decibel is a unit of:
a. Wavelength.
b. Frequency.
c. Amplitude.
d. Loudness.
Physics Exam6,14
2007-01-05 10:54 pm
回答 (1)
2007-01-06 3:03 am
✔ 最佳答案
6(rho1)A1v1=(rho2)A2v2
rho :density
[15.0/2]^2*pi*1.2=[2.5/2]^2*pi*v
v=176 m/s
答案是A
14
The decibel is a unit of:
答案是D
The decibel (dB) is used to measure sound level
2007-01-05 19:03:46 補充：
5.25[15.0/2]^2*pi*1.2=1.29[2.5/2]^2*pi*v
收錄日期: 2021-04-25 16:49:22
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070105000051KK01563