Transcript Sport Application and Newton`s Laws of Motion

Sport Application and
Newton’s Laws of Motion
1st Law
• Every body persists in its state of rest or of uniform motion
in a straight line unless it is compelled to change that state
by forces impressed on it
• OR
• A body remains at rest or in a state of uniform motion in a
straight line unless acted upon by an applied force.
• This is also described as the Law of Inertia because it
describes the quality of needing a force to change the
state of rest or motion
2nd Law
• The change of motion is proportional to the motive
power impressed, and is made in the direction of the
right(straight) line in which the force is impressed.
• Or
• If a body of mass(m) has an acceleration(a), the force
acting on it is (f), defined as the product of its mass
and acceleration (F=ma)
• Law of Acceleration-the acceleration of an object that
is acted upon by a force is directly proportional to the
force and inversely proportional to the mass of the
object
rd
3
Law
• To every action there is always opposed an
equal reaction; or, the mutual actions of two
bodies upon each other are always equal
and directed to contrary parts
• Or
• To every action there is an equal and
opposite reaction
• Law of Action-Reaction
Classes of Levers and Lever Systems
• The lever system consists of an axis of rotationFulcrum(joints) around which a rigid lever(bones) move,
by a force(muscle)
•
• The system consists of a 1. Force Arm- applied forceexternal force, weight, object
•
2. Resistance Arm-resists
motion (resistive force- muscle force)
•
3. Fulcrum - axis of rotation
•
• There are 3 classes of lever they are classified according to
the positions of the axis, force arm and resistance arm
1st Class
• the Fulcrum is in the middle between the force and
the resistance
___________________________
Force
Resistance
Fulcrum
• This lever favors SPEED or FORCE depending on
the relative length of the force and resistance
arms.
2nd Class
• Resistance is in the middle between the fulcrum
and the force
Applied Resistance
___________________________
Fulcrum
Applied Force
• Range of Motion is sacrificed to gain FORCE
Output. Resistance arm is always longer than the
Force arm
3rd Class
• Applied Resistance is in the middle between the
fulcrum and the Applied Force The Force arm
is always longer than the arm. Therefore this
favors SPEED over FORCE.
Applied Force
_________________________
Fulcrum
Applied Resistance