lecture 1 introduction
TRANSCRIPT
enter ⟩⟩Department of Engineering Sciences
Statics of Rigid Bodies
STATICS OF RIGID BODIES
STATICS OF RIGID STATICS OF RIGID BODIESBODIES
Chapter 1: Introduction
DEFINITIONDEFINITION
Mechanics• the study of the relationship among forces and
their effects on bodies.• the science which describes and predicts the
conditions for rest and motion of bodies under the action of forces.
• a physical science (for it deals with physical phenomena)
Statics of Rigid Bodies
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MECHANICSMECHANICS
Statics of Rigid Bodies
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MECHANICS
RIGID BODIES DEFORMABLE BODIES
FLUIDS
STATICS DYNAMICS INCOMPRESSIBLE COMPRESSIBLE
bodies at rest
bodies in motion
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Statics of Rigid Bodies
What is a FORCE?What is a FORCE?represents the action of one body on another
that tends to change the state or state of motion of a body.
may be exerted by actual contact or at a distance (e.g. gravitational and magnetic forces).
characterized by its point of application, magnitude and direction.
represented by a vector.
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Statics of Rigid Bodies
Effects of a FORCEEffects of a FORCE• development of other forces(reactions or internal forces)• deformation of the body• acceleration of the body
Applied Force
Development of other forcesDevelopment of other forces
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Applied Force
Reaction
Development of force or forces at points of contact with other bodies (reactions).
Development of other forcesDevelopment of other forces
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Development of forces within the body itself (internal forces)
A A
Applied Force
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Deformation of the bodyDeformation of the body
Applied Force
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Acceleration of the bodyAcceleration of the body
Applied Force
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Statics of Rigid Bodies
Properties of a FORCEProperties of a FORCEA force represents the action of one body on another and is generally characterized by its point of application, its magnitude, and its direction. Forces acting on a given particle, however, have the same point of application.
10N
30o10N
30o
• Magnitude 10N• Direction 30 degrees (upwards or downwards)• Point of Application – line of action (LOA) dashed line having an angle 30 degrees
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Statics of Rigid Bodies
DEFINITIONDEFINITIONParticles - in the context of this course, does not indicate “smallness of size”, rather, it means that the shape and size of the object does not significantly affect the solution of the problems under consideration.
Rigid Bodies - the problems considered in this course are assumed to be non-deformable. Again, such assumption does not significantly affect the solution of the problems under consideration.
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BASIC QUANTITIES & UNITSBASIC QUANTITIES & UNITS
Statics of Rigid Bodies
Quantity SI ENGLISH
Length m (meter) ft (feet)
Mass kg (kilogram) slugs
Time s (seconds) s (seconds)
Force kg*m/s^2 or N lbs Newton (pounds)
Acceleration due to gravity
g = 9.81 m/s^2 or g = 32.2 ft/s^2