What is the study of forces and their effects
Mechanics
Mechanics that deals with geometry of the motion of objects, displacement, acceleration, velocity
Kinematic
Study of relationships between force system acting on the body and changes it produces in body motion
Kinetics
Uses principles of mechanics for solving problems related to structure and function
Biomechanics
What are the three examples of Scalars
Distance
Speed
Mass
MAGNITUDE ONLY
What are the 6 vectors
Displacement Velocity Acceleration Weight Momentum Force
MAGNITUDE AND DIRECTION
What is speed
Distance/Time
Ignorant of direction
Scalar quantity
What is velocity
Displacement/time
Direction aware
What is acceleration
Change in Velocity/Time
Vector Quantity, so means it has direction associated with it
What is mass
Amount of matter that is in the object
G or KG
Scalar quantity
What is weight
measure in N
Is the force of gravity working up on the object
1 kilogram=10 newtons=2.2 pounds
What is momentum
Mass*Velocity
P=m*v
Vector quantity
What is force
Action of push or pull
Measure in newtons
Vector quantity
F=m*a
What is the law of inertia
An object at rest stays at rest and an object in motion remains in motion unless acted upon by an outside force
A system in ___________ is either at rest or moving with a constant velocity
Equilibrium
Law of force and Acceleration
Newtons 2nd law
The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object
The observed change in motion is called acceleration
The law of action and reaction
Newtons 3rd law
For every action, there is an opposite and equal reaction
What is normal stress
The intensity of force perpendicular to the surface on which it acts
What is shear stress
The intensity of force parallel to the surface on which it acts
What is static friction
Exists when two contacting surfaces are not currently sliding relative to each other but do posses the potential for movement
This is the ratio required to initiate a sliding motion between two bodies
Coefficient of static friction
What is kinetic friction
Friction in cases when the two surfaces are already sliding relative to each other
Aka= dynamic friction
As soon as a applied parallel force exceeds the static friction force and the object begins to slide, friction force actually decreases
Coefficient of kinetic friction
What is pressure
Is the magnitude of a applied force acting over a given area
p= F/A
Measured as Newtons/meter or pascals (PA)
What is tensile strength
Max stretch a material can withstand without rupture of skin = 9.25 N/mm
What is work
Is performed when an object is displaced by the application of a force
Force x Distance
Measure in joules
Can be positive or negative
What is kinetic energy
The energy an object posses due to motion
Measure in joules
KE=1/2mv2
Changes in velocity have large effects on kinetic energy
What is angular motion
The path of motion around a fixed axis and therefore in a circular path
What is angular velocity
Time rate of change of angular position of a rotating body
Degrees or radians per unit of time
What is angular acceleration
Time rate of change of angular velocity of a rotating body
What is the axis of rotation
The point about which a body rotates
What is the lever arm
Aka force arm, moment arm
Perpendicular distance from an axis of rotation to a line along which a force acts
What is torque
Product of force and lever arm
We move due to what force
Torque
A _______________________ consists of a rigid or semi rigid object (lever) that is capable of rotating about an axis (fulcrum)
Lever system
What is a type one lever
Fulcrum between the effort and load, ex. See saw
What is a type 2 lever
Load is between the fulcrum and effort
Ex. Stapler, wheelbarrow
What is a type 3 lever
Effort is between the fulcrum and the load’
Ex. Fishing rod, broom
Example of type 1 lever in body
Neck
Example of type 2 lever in body
Achilles and calcaneous
Example of type 3 lever in body
Elbow joint
Most common
> 1
Force advantage
<1
Speed and range of motion
What is mechanical advantage
Mm/Mr
If the fulcrum is directly in the middle of the lever, the ratio is 1.00 which force has an advantage
Neither