Quiz 1 Flashcards
Study of forces and their effects
Mechanics
Motion of objects, including: displacement, acceleration and velocity
Kinematics
Study of relationships btw force system and the changes it produces in body motion
Kinetics
Uses principles of mechanics for solving problems related to bio/physiologic systems
Biomechanics
Scalars are ____ only
Magnitude
Examples of scalars
Distance
Speed
Mass
Vectors are ____ and ____
Magnitude and direction
Examples of vectors
Displacement Velocity Acceleration Weight Momentum Force
How much ground an object has covered during its motion
Distance
Scalar quantity
How far out of place an object is; overall change in position
Displacement
Vector quantity
How fast an object is moving
Speed
Scalar quantity
Speed =
Distance/time
Speed is ____ of direction
Ignorant
Rate at which an object changes its position
Velocity
Vector quantity
Velocity =
Displacement/time
Velocity is direction ____
Aware
HVLA
High velocity low amplitude
Rate at which an object changes its velocity
Acceleration
Acceleration =
Velocity/time
Acceleration is a
Vector quantity
Direction of acceleration depends on
Object speeding up/slowing down
Object moving in + or - direction
Amount of matter contained by the object
Mass
Mass is a
Scalar quantity
Constant
Force of gravity acting upon that object
Weight
Weight is a
Vector quantity
As centers of two bodies are moved farther apart, the gravitational attraction btw them ___
Dec.
and vice versa
Weight is ___ on the poles
Higher — your center closer to center of earth
Quantity of motion an object possesses
Momentum
Momentum =
Mass x velocity
Momentum is a
Vector quantity
Something that has a lot of momentum is going to be
Hard to stop
Action upon a body causing it to deform or move
Force
Newton is the amount of force required to
Give 1kg mass acceleration of 1meter/s2
Force =
Mass x acceleration
To increase force we either inc ___ or ____
Mass; acceleration
Or both
Resistance to have its state of motion changed by application of a force
Inertia
Law of Inertia (Newtons 1st law)
An object at rest stays at rest; an object at motion stays in motion
UNLESS acted upon by an unbalanced force
A system in equilibrium is either
At rest or moving w/ constant velocity
Law of Force and Acceleration (Newton’s 2nd Law)
Acceleration of an object directly depends on net force acting up it
Inversely upon mass of the object
Observed change in motion
Acceleration
Law of action and reaction (newton’s 3rd Law)
For every action, there is an equal and opposite reaction
Normal stress
Intensity of force perpendicular to surface on which it acts
Shear stress
Intensity of force parallel to surface on which it acts
Higher friction coefficient means that
It is harder to get an object into motion
Static friction
Two contacting surfaces not currently sliding but have potential for movement
Kinetic friction
Two surfaces are already sliding relative to each other
Kinetic friction AKA
Dynamic friction
Magnitude of applied force acting over a given area
Pressure
P =
F/A
When an object is displaced by application of force
Work
Work =
Force x distance
Work can be
Positive or negative
Changes in velocity have ___ effects on kinetic energy
Large
Because velocity is squared
KE =
1/2mv^2
Axis of rotation
Point about which a body rotates
Lever arm
Perpendicular distance from axis of rotation
Product of force and lever arm; tendency of force to rotate an object around an axis
Torque
We move because of
Torque
Muscles apply eccentric forces to bones
Type 1 lever
Fulcrum between effort and load/resistance
Type 2 lever
Load/resistance between fulcrum and effort
Type 3 lever
Effort between fulcrum and load/resistance
Type 1 lever example on body
Head/neck
Type 2 lever example on body
Leg/ankle
Type 3 lever example on body
Elbow
Moment arm =
Force x lever arm distance
> 1 mechanical advantage in
Force
<1 mechanical advantage in
Speed and range of motion
If fulcrum is directly in middle of lever, mechanical advantage is
1.00 — neither force has an advantage
Effort farther than load from fulcrum = lever at a ______
Mechanical advantage
Speed and distance = disadvantage
Effort nearer than load to fulcrum = lever at a _______
Mechanical disadvantage
Speed and distance = advantage