FUNDAMENTAL QUANTITIES OF MECHANICS

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FUNDAMENTAL QUANTITIES OF MECHANICS
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Fundamental Quantities

• Space
• Time
• Matter
• Force

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Fundamental Quantities

• Space
• geometric region in which the physical events of
  interest in mechanics occur
• region extends without limit in all directions
• points in space can be determined relative to
  some reference system
• types of reference systems
• inertial
• relative

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Fundamental Quantities

• Time
• an interval between two events
• measurements
• solar year time for earth to orbit the sun
• periodic vibrations of isotope cessium 133 (an
  atomic clock)

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Fundamental Quantities

• Matter
• any substance that occupies space
• body matter bounded by closed surface
• inertia property of a body that causes it to
  resist change in motion
• mass quantitative measure of inertia

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Fundamental Quantities

• Force
• the action of one body on another
• contact forces a push or pull directly on a body
• levers, rods, cables
• bodies at a distance forces of attraction or
  repulsion
• gravity, magnetism, atomic

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Newtons Laws of Motion

• 1st Law A particle originally at rest will
  remain at rest a particle originally moving with
  a constant velocity will continue to move with a
  constant velocity along a straight line, unless
  the particle is acted on by an unbalanced force.

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Newtons Laws of Motion

• 2nd Law When a particle is acted on by an
  unbalanced force, the particle will be
  accelerated in the direction of the force the
  magnitude of the acceleration will be
  proportional to the force and inversely
  proportional to the mass of the particle.

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Newtons Laws of Motion

• 3rd Law For every action there is an equal and
  opposite reaction. The forces of action and
  reaction between two contacting bodies are equal
  in magnitude, opposite in direction, and
  collinear.

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Bodies

• Particle
• an object whose size and shape can be ignored
  when studying its motion (or lack of motion)
• only the position of the mass center of the
  particle need be considered
• orientation, rotation, and size play no role in
  describing the motion of the particle

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Bodies

• System of Particles
• two or more particles making up the object of
  interest
• the distance between centers of mass of the
  individual particles may change with time or space

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Bodies

• Rigid Body
• a system of many (infinite number?) particles in
  which the relative position of the particles
  comprising the body remain constant at all times
  and under all loads
• the size and shape of the body remain constant

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Bodies

• Deformable Body
• a system of many (infinite number?) particles in
  which the relative position of the particles
  comprising the body does not remain constant at
  all times and under all loads
• the size and shape of the body change under load

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Mass / Weight

• Mass of a body
• an absolute quantity, independent of the position
  of the body and independent of the surroundings
  in which the body is placed
• Weight of a body
• the gravitational attraction exerted on the body
  by another massive body (the earth, the moon,
  etc.)

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Mass / Weight
m1
Fg
r
Fg
m2
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• End