Vector Mechanics for Engineers: Dynamics MECN 3010

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Vector Mechanics for Engineers Dynamics MECN
3010

• Department of Mechanical Engineering
• Inter American University of Puerto Rico
• Bayamon Campus
• Dr. Omar E. Meza Castillo
• omeza_at_bayamon.inter.edu
• http//www.bc.inter.edu/facultad/omeza

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Syllabus

• Catalog Description Kinematic analysis of
  particles and rigid bodies in one, two and three
  dimensions. Emphasis in curvilinear motion.
  Application of the Newton s second law, energy
  and work, impulse and momentum principles on
  particles and rigid bodies.
• Prerequisites MECN 3005 Vector Mechanics for
  Engineers Statics.
• Course Text Hibbeler, R.C., Engineering
  Mechanics - Static and Dynamics, 12th. Ed.,
  Prentice Hall, 2009.

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Syllabus

• Absences On those days when you will be absent,
  find a friend or an acquaintance to take notes
  for you or visit the web page. Do not call or
  send an e-mail the instructor and ask what went
  on in class, and what the homework assignment is.
• Homework assignments Homework problems will be
  assigned on a regular basis. Problems will be
  solved using the Problem-Solving Technique on any
  white paper with no more than one problem written
  on one sheet of paper. Homework will be
  collected when due, with your name written
  legibly on the front of the title page. It is
  graded on a 0 to 100 points scale. Late homework
  (any reason) will not be accepted.

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Syllabus

• Problem-Solving Technique
• Known
• Find
• Assumptions
• Schematic
• Analysis, and
• Results
• Quiz There are several partial quizzes during
  the semester.
• Partial Exams and Final Exam There are three
  partial exams during the semester, and a final
  exam at the end of the semester.

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Course Grading

• The total course grade is comprised of homework
  assignments, quiz, partial exams, and final exam
  as follows
• Homework 25
• Quiz 25
• Partial Exam (3) 25
• Final Exam 25
• 100
• Cheating You are allowed to cooperate on
  homework by sharing ideas and methods. Copying
  will not be tolerated. Submitted work copied from
  others will be considered academic misconduct and
  will get no points.

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Course Materials

• Most Course Material (Course Notes, Handouts, and
  Homework) on Web Page of the course MECN 3010
• http//facultad.bayamon.inter.edu/omeza/
• Power Point Lectures will posted every week or
  two
• Office Hours G235
• Contact Email mezacoe_at_gmail.com

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Tentative Lecture Schedule
Topic Lecture
Kinematics of a Particle 1
Kinetics of a Particle Force and Acceleration
Kinetics of a Particle Work and Energy
Kinetics of a Particle Impulse and Momentum
Planar Kinematics of a Rigid Body



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Reference

• Bedford, Anthony. and Fowler Wallace.,
  Engineering Mechanics - Statics and Dynamics,
  5th Ed., Prentice Hall, 2008.
• Beer, F.P. and Johnston, E.R., Vector Mechanics
  for Engineers - Statics and Dynamics, 8th Ed.,
  McGraw-Hill, 2007.
• Meriam J. L.,Kraige L. G., Engineering Mechanics
  Statics and Dynamics, 6th Ed., John Wiley Sons,
  2006

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Introduction and Basic Concepts
"Lo peor es educar por métodos basados en el
temor, la fuerza, la autoridad, porque se
destruye la sinceridad y la confianza, y sólo se
consigue una falsa sumisión Einstein Albert

• Topic 1 Kinematics of a Particle

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Chapter Objectives

• To introduce the concepts of position,
  displacement, velocity, and acceleration.
• To study particle motion along a straight line
  and represent this motion graphically.
• To investigate particle motion along a curve path
  using different coordinate systems.
• To present an analysis of dependent motion of two
  particles.
• To examine the principles of relative motion of
  two particles using translating axes.

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12.1 Introduction. What is dynamics ???

• Study the accelerated motion of a body

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12.1 Introduction. What may happen if dynamics
is not applied properly ???
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12.2 Rectilinear Kinematics Continuous Motion
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12.2 Rectilinear Kinematics Continuous Motion
c. Velocity If the particle moves through a
displacement ?s during the time interval ?t, the
average velocity of the particle during this time
interval is If we take smaller and smaller
values of , the magnitude of becomes smaller and
smaller. The instantaneous velocity is a vector
defined as
The velocity can be positive () or negative
(-). The magnitude of the velocity is called
speed, and it is generally expressed in units of
m/s or ft/s.
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12.2 Rectilinear Kinematics Continuous Motion
d. Acceleration Provided the velocity of the
particle is known at two points, the average
acceleration of the particle during the time
interval ?t, is defined as The ?v v - v
represents the difference in the velocity during
the time interval ?t The instantaneous
acceleration is a vector defined as
The acceleration can be either positive () or
negative (-). The magnitude of the acceleration
is generally expressed in units of m/s2 or ft/s2.
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12.2 Rectilinear Kinematics Continuous Motion
Relating the equations
It is obtained an important differentia relation
involving displacement, velocity and acceleration
Constant Acceleration, aac
Velocity as a Function of Time. Integrate
acdv/dt, assuming that initially vv0 when t0
(1)
Constant Acceleration
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12.2 Rectilinear Kinematics Continuous Motion
Position as a Function of Time. Integrate
vds/dtv0act, assuming that initially ss0 when
t0
(2)
Constant Acceleration
Velocity as a Function of Position. Substituting
the previous equation (1) into the (2) equation
or integrate vdvacds, assuming that initially
vv0 at ss0
Constant Acceleration
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Application Problems
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Homework1 ? WebPage
Due, Thursday, February 01, 2012
Omar E. Meza Castillo Ph.D.