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1
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- Some knowledge of basic biomechanics is necessary to understand the
action of the muscles in moving the body and objects.
- The external forces that affect the body during movement.
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2
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- Subdivided into Statics and Dynamics
- Dynamics has two subdivisions
- Kinematics – Description of motion: displacement, time, velocity,
acceleration, angle, angular velocity, angular acceleration
- Kinetics – Causes of motion – forces and torques
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3
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- To balance multiple forces
- To enhance force in an attempt o reduce the total force needed to
overcome a resistance
- To enhance range of motion and speed of movement so that resistance may
be moved farther or faster than the applied force.
- To alter the resulting direction of the applied force.
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4
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- Three types of machines in the body
- Levers
- Wheel and axles
- Pulleys
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5
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- A rigid bar that turns about an axis of rotation, or fulcrum.
- The lever rotates around the axis of rotation as a result of a force
(Effort, E) being applied to it to cause its movement against a
resistance, R.
- Bones are rigid bars, joints are levers, muscles provide the Effort
force.
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6
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- First Class: EFR
- Second Class: FRE
- Third Class: FER
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7
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8
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9
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10
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- First Law of motion: A body in
motion tends to stay in motion at the same speed in a straight line
unless acted upon by an unbalanced force; a body at rest will tend to
stay at rest until acted upon by an unbalanced force.
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11
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- A change in the acceleration of a body occurs in the same direction as
the unbalanced force that caused it.
The change in acceleration is directly proportional to the force
causing it and inversely proportional to the mass of the body.
- Force = mass x acceleration
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12
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- F = ma
- Since a = Dv/Dt = (vf – vi)/
(tf – ti)
- F = m (vf – vi)/ (tf – ti)
- F = (m vf - m vi)/ (tf – ti)
- mv is momentum
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13
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- For every action there is an equal and opposite reaction.
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Notes
