EM406 Examination I: Problems and Solutions for Mechanical Systems, Exams of Engineering

The problems and solutions for examination i of the em406 course, focusing on mechanical systems. It includes problems related to springs, second order systems, slender beams, and packed objects. Students are required to calculate natural frequencies, identify damping types, determine equations of motion, and find steady state responses.

Typology: Exams

Pre 2010

Uploaded on 08/18/2009

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Name ___________________________ Section _____________________
EM406
Examination I
September 23, 2004
Problem Score
1 /20
2 /25
3 /30
4 /25
Total /100
Show all work for credit
AND
Turn in your signed help sheet
pf3
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pf5

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Download EM406 Examination I: Problems and Solutions for Mechanical Systems and more Exams Engineering in PDF only on Docsity!

Name ___________________________ Section _____________________

EM

Examination I

September 23, 2004

Problem Score

Total /

Show all work for credit

AND

Turn in your signed help sheet

EM406 Examination I Problem 1 September 21, 2004

For all parts of problem 1 you must show all work for credit

Problem 1a A spring has a mass of 0.3 kg and a spring constant of 40 N/m. Estimate the natural frequency of the spring.

a) 0.0866 rad/s b) 11.55 rad/s c) 20 rad/s d) 24.08 rad/s

Problem 1b A second order system is excited harmonically, f(t) = 2 sin(0.785t) and the input and total response (transient and steady state) are shown below. What is the phase angle in radians between the input and the output?

k, m

0

1

2

3

4

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Tim e (s)

EM406 Examination I Problem 2 September 21, 2005

The slender beam of mass, M, and length, L, carries two masses and is supported by a spring k and a dashpot c. Using the angle, θ, measured from the static equilibrium point as a coordinate determine: a) the equation of motion in terms of θ b) the natural frequency in terms of the parameters given c) the critical damping in terms of the parameters given

k

m 3m

O

a

b

c M

L

EM406 Examination I Problem 3 September 21, 2004

A 4 kg piston slides with viscous friction inside a cylinder. The upper end of an elastic spring that supports the piston moves with a harmonic motion x 1 = 10 sin12t where x is in millimeters. The spring constant is 400 N/m and the damping constant is 20 N-s/m. Determine: a) the equation of motion for the mass b) the steady state response of the mass. c) A coworker was asked to find the range of frequencies where the amplitude is less than 11 mm and using Maple she found

Using her results, for what frequencies will the amplitude be less than 11 mm? x 1 = 10 sin12t

k

c

{ r =-0.3248666148 }, { r =-1.282365659 }, { r =1.282365659 },{ r =0.3248666148}