second exam of "vibration and waves " phyisics

Jordan University of Science & Technology

Department of Physics/ Physics 281 Second Exam, First Semester 2014-2015

االسم: الرقم الجامعي:

Q1) In the shown figure, the three masses are coupled with two different springs and they

are free to move over a smooth surface.

a) Write the equation of motion for each mass……………… (6 points)

b) What is the number of normal modes and explain why?........ (2 points)

Q2) a) Describe the successive motion of each mass in the shown coupled pendulums

(without using equations) if at t =0 both masses are at rest and, x =0, y = -A

…………….(4 points)

b) What is the total energy of the system in this case and what is the energy associated

with each mode? ………………..((6 points)

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Q3) A loaded string consists of 5 masses spaced evenly.

a) Just by drawing, describe the motion of the system at the lowest possible natural

frequency? ……………………….(2 points)

b) Mathematically, describe the motion of the third mass at the lowest natural

frequency i.e. what is y(t)? ………(2 points)

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Q4) A transvers wave is described by y = 5sin (3t+4x)

a) Find the phase velocity and what does it mean? (2 points)

b) Find the particle velocity and what does it mean? (2 points)

c) Is this wave moving to the right or to the left and explain why in details?

………………….(2 points)

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Best of luck