su09EIIIS

# su09EIIIS - Physics 53 Summer 2009 Exam III Solutions In...

This preview shows pages 1–3. Sign up to view the full content.

Physics 53 Summer 2009 1 Exam III Solutions In questions or problems not requiring numerical answers, express the answers in terms of the symbols given, and standard constants such as g . If numbers are required, use g = 10 m/s 2 . Part A: Multiple choice questions. Check the best answer. Each question carries a value of 4 points. 1. A hydraulic jack consists of a cylinder (1) with a small cross section area a , connected by a pipe to a cylinder (2) with larger cross section A . Each cylinder is fitted with a piston that can move vertically, and the system is filled with an incompressible fluid. A heavy load to be raised rests on the piston in 2; the total mass of the load and the piston is M . A force F 1 is exerted downward on the piston in 1, resulting in an upward force F 2 on the piston in 2 . Which of the following is NOT true? The pressure in both cylinders is the same. As the piston in 1 moves down distance d the piston in 2 moves up distance d ! ( a / A ) . To lift the piston in 2 and the load at constant speed, we must have F 1 = Mg ! ( A / a ) . [ F 1 = Mg ! ( a / A ) . The whole point of the device is that F 1 is less than Mg .] The work done by F 1 is equal to the work done by F 2 . 2. Waves 1 and 2 exist simultaneously in a medium, described by the functions y 1 ( x , t ) = 0.01cos(10 ! x " 100 ! t ) y 2 ( x , t ) = 0.01cos(9 ! x " 90 ! t ) Wave 1 travels faster than wave 2. [Same speed] Superposition of these waves produces a standing wave. The waves produce 5 beats/s. [Frequencies are 50 and 45 Hz] None of the above is true. 1 2

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Physics 53 Summer 2009 2 3. The frequencies of successive harmonics of an organ pipe are 250 and 350 Hz. The fundamental frequency for this pipe is 250 Hz. The fundamental frequency for this pipe is 50 Hz. The pipe is open at both ends. [Closed at one end] None of the above is true. 4. Two sounds produce loudness levels of 90 db and 60 db for a listener. The ratio of the intensities of these sounds is: 3/2.
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern