MECE 102: Engineering Mechanics Lab
A First Year Course in
Newtonian Mechanics, Experimentation,
and Computer Tools
Created by the Faculty of the Mechanical Engineering
Department in the Kate Gleason College of Engineering at RIT
Week 3 Lecture
Newton’s 1st and 2nd Laws
• We will study the constrained linear motion of a single
body of mass m this week.
• We will be using the Ultrasonic Transducer again.
• The concept of Vectors will be introduced and utilized
when analyzing the experimental data sets.
• The concept of FRICTION is introduced.
CLICKER: Which of the following statements is
FALSE?
• Select your Answer:
A.
B.
C.
D.
E.
Velocity is the time rate of change of position.
Acceleration is the time rate of change of velocity.
Velocity is the time rate of change of acceleration.
Snap is the time rate of change of Jerk.
The RIT Mascot is a Bengal Tiger.
CLICKER: Which of the following statements is
FALSE?
• Select your Answer:
A.
B.
C.
D.
E.
Velocity is the time rate of change of position.
Acceleration is the time rate of change of velocity.
Velocity is the time rate of change of acceleration.
Snap is the time rate of change of Jerk.
The RIT Mascot is a Bengal Tiger.
FACET Problem Solving Method
Recall from Recitation and Ch. 1.4.2 the problem
solving method we will be using in class:
• Formulate
• Assume
• Chart
• Execute
• Test
• Iterate
FORMULATE: State the Known Information
FORMULATE: State the Known Information
FORMULATE: Identify Assumptions
CHART: Schematic Diagram
CHART: Schematic Diagram
Figure 3.2: Schematic Diagram of an Experiment to Measure
an Object Sliding Down an Inclined Plane toward Earth.
CHART: Schematic Diagram
CLICKER: Amontons’ First Law States which of the
following?
• Select your Answer:
A. f = N
B. f  N
C. f  N
D. f  µN
E. f  µN
CLICKER: Amontons’ First Law States which of the
following?
• Select your Answer:
A. f = N
B. f  N
C. f  N
D. f  µN
E. f  µN
Amontons’ 2nd Law States that ……
CLICKER: Amontons’ First Law States which of the
following?
• Select your Answer:
A. f = N
B. f  N
C. f  N
D. f  µN
E. f  µN
Amontons’ 2nd Law States that “the force of friction
is independent of the apparent contact area.”
EXECUTE: Recall Governing Equations
CLICKER: Which of the following values is related to
the friction force associated with incipient
(impending) motion of an object?
• Select your Answer:
A. Mean horizontal acceleration
B. Mean vertical acceleration
C. Dynamic coefficient of friction
D. Static coefficient of friction
CLICKER: Which of the following values is related to
the friction force associated with incipient
(impending) motion of an object?
• Select your Answer:
A. Mean horizontal acceleration
B. Mean vertical acceleration
C. Dynamic coefficient of friction
D. Static coefficient of friction
CLICKER: For a given interface between two surfaces,
the Dynamic coefficient of friction is always greater
than the Static coefficient of friction.
• Select your Answer:
A. True
B. False
CLICKER: For a given interface between two surfaces,
the Dynamic coefficient of friction is always greater
than the Static coefficient of friction.
• Select your Answer:
A. True
B. False
Thought Experiment
• Consider a block of mass, m, resting on a
horizontal surface.
• Plot the relationship between an applied
horizontal force, Fapplied, and the resulting
friction force, Ffriction.
Vectors
Vector representation using 2D Cartesian Coordinates
𝑖
Vector representation using 2D Cartesian Coordinates
Vectors Obey the Commutative Law …..
Vectors Obey the Commutative Law …..
And the Associative Law …..
CLICKER: Which of the following coordinate systems
may be used when describing a Vector?
• Select your Answer:
A. Cartesian (x, y, z)
B. Polar (r, )
C. Normal , Tangential
D. All of the above
CLICKER: Which of the following coordinate systems
may be used when describing a Vector?
• Select your Answer:
A. Cartesian (x, y, z)
B. Polar (r, )
C. Normal , Tangential
D. All of the above
CHART: Vector Diagrams
𝒏
𝒕
EXECUTE: The Case of Incipient Motion, s
EXECUTE: The Case of Motion, d
Week 3 Constrained Linear Motion
Experimental Apparatus
Week 3 Constrained Linear Motion
Experimental Apparatus
STUDIO: Central Difference Estimate for Velocity
Homework
• Prior to LAB tomorrow
• Read section 3.2 of the textbook
• Watch Week 3 LAB Videos
• Complete the on-line LAB quiz in myCourses
• Attempt to solve all assigned chapter problems in your logbook
before RECITATION.
• WEEK 3 HW Problem Set from Section 3.5:
3
8 parts b, d
9
10 parts a, c
14
16 parts b, c
18
20
• Lab Report #2 is due Monday by 6:00pm!
The Scribe must upload the LAB REPORT to the myCourses
Lab Report #2 Dropbox by 6:00pm Monday!
Questions?