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Class Today •  Print notes and examples

•  Syllabus and schedule

•  Class website

•  Mastering Engineering

•  Mec Movies

•  Introduction to Statics

•  Vectors

My Lab and Mastering (7.5%) •  Web based interface used for submitting

text book homework problems.

•  Homework submitted and graded online. – Need to work out problems by hand !!!

– Points deducted for multiple attempts on multiple choice questions; nominal amount deducted for multiple attempts on other problems.

•  Register through Canvas using access code provided on handout.

Written Homework (7.5%) •  Random problems may be collected at

any time (from the Mastering homework)

•  Please all work to class.

•  Mastering grades your answer, problems collected in class are graded on process. –  Is it a complete solution?

– Can someone else follow your steps?

–  Is it readable?

Engineering Mechanics •  Rigid Body Mechanics

– Statics deals with equilibrium of bodies, those that are either at rest or moving at a constant velocity.

– Dynamics deals with bodies undergoing accelerated motion

•  Deformable Body Mechanics

•  Fluid Mechanics (incompressible, compressible)

Why Study Statics First?

•  It is a springboard for the rest of design…

•  Design most often deals with bodies in equilibrium

Fundamental Concepts •  Particle - mass, but size is

neglected

•  Rigid Body – combination of large number of particles that remain in a fixed position relative to each other

•  Concentrated Force

Image copyright 2013, Pearson Education, publishing as Prentice Hall

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Units of Measurement Scalars and Vectors

•  Scalar - measures magnitude ONLY (length, mass, volume)

•  Vector - measures magnitude AND direction (notably forces and moments are vectors)

Using Vector Components

•  Breaks down vector into rectangular components along 2 or 3 axes.

•  Scalar notation simply notes resultant and / or component magnitudes

•  Cartesian vector notation notes magnitude along with unit vector designation i, j, k.

Image copyright 2013, Pearson Education, publishing as Prentice Hall

Finding Vector Components

Image copyright 2013, Pearson Education, publishing as Prentice Hall

•  Can be calculated using trigonometric relationships and projection angles

Unit Vector •  Defines direction of vector •  Has magnitude of 1.0 •  Find by dividing each vector

component by its magnitude

•  Coordinate direction angles designate direction of each component relative to vector

Image copyright 2013, Pearson Education, publishing as Prentice Hall

Position Vector •  Specifies location of a point in space relative to

another point. •  Magnitude measures

distance •  Find by subtracting TAIL coordinates from TIP

coordinates. (TIP - TAIL)

Image copyright 2013, Pearson Education, publishing as Prentice Hall

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Forces as Vectors

Force is expressed as a Cartesian vector

by multiplying the magnitude of the force

by each component of the corresponding

unit vector

Vector Addition – Graphically done by placing tip to tail

– Mathematically done by adding like components

Image copyright 2013, Pearson Education, publishing as Prentice Hall

Dot Product •  Can find the scalar component of a

vector parallel to or perpendicular to a given line.

•  Can find the angle between two lines

•  Multiply like components

Image copyright 2013, Pearson Education, publishing as Prentice Hall

Dot Product: Component of a vector acting along an axis