Test 2- Part 2: Laws of Motion Flashcards
What are the two types of motion?
Linear motion
Angular motion
Motion cannot occur w/ out what?
Force (muscular system)
What is linear motion aka?
Translatory motion
Distance that a system moves in a straight line
Linear displacement
What are the two types of linear motion/.
Rectilinear motion
Curvilinear motion
Motion along a straight line
Rectilinear motion
Motion along a line
Linear motion
Motion along a curved line
Curvilinear
Rotation around an axis
Angular (rotary motion)
Where in the body are the axis of rotation provided by?
Joints
_________ motion of joints produces the _______ motion of walking
Angular
Linear
Change in position or location of an object from its original point of reference
Displacement
Actual sum length it is measured to have traveled
Distance (path of movement)
Change in location of a rotating body
Angular displacement
Distance that a system moves in a straight line
Linear displacement
How fast an object is moving, or distance that an object moves in a specific amount of time
Speed
Rate at which an object changes position. Includes the direction & describes the rate of displacement
Velocity
Explain the law of inertia
A body in motion tends to remain in motion at the same speed in a straight line unless acted on by a force; a body at rest tends to remain at rest unless acted on by a force
Resistance to action or change (acceleration/deceleration)
Inertia
How do muscles produce force?
Stop motion Start motion Accelerate motion Decelerate motion Change direction of motion
The greater an objects mass, the greater the __________
Inertia
More mass=
More force needed to significantly change an object’s inertia
Any activity carried out at a steady pace in a constant direction will ___________ energy
Conserve (endurance runners)
Explain the law of acceleration
A change in the acceleration of a body occurs in the same direction as the 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.
The rate of change in velocity
Acceleration
The amount of matter in the body
Mass
Explain the law of reaction
For every action there is an opposite reaction
Force on the surface reaction to the force we place on it
Ground reaction force
We provide the _______ force while the surface provides the _______ force
Action
Reaction
Force that results from the resistance between surfaces of two objects from moving upon one another
Friction
On slick (wet) ground our shoe friction is ________ & we are more likely to slip
Reduced
The amount of friction between two objects that have not yet begun to move
Static friction
Friction occurring between two objects that are sliding upon one another
Kinetic friction
_______ friction is always greater than ________ friction
Static
Kinetic
How might you increase static friction?
Increasing the normal or perpendicular forces pressing the two objects together such as in adding more weight to one object sitting on the other object
Ration of force needed to overcome the friction over the force holding the surfaces together
Coefficient of friction
Resistance to an object rolling across a surface such as a ball rolling across a court or a tire rolling across a ground
Rolling friction
The ability to control equilibrium (either static or dynamic)
Balance
State of zero acceleration where there is no change in the speed or direction of the body, maybe either static or dynamic
Equilibrium
Body is at rest or completely motionless
Static equilibrium
All applied & inertial forces acting on the moving body are in balance, resulting in movement with unchanging speed or direction
Dynamic equilibrium
To control equilibrium & achieve balance, ________ needs to be _________
Stability
Maximized
Change in the body’s acceleration; disturbance of the body’s equilibrium
Stability
Point at which all of the body’s mass & weight are equally balanced or equally distributed in all directions
Center of gravity
How is stability enhanced?
Finding body’s center of gravity & appropriately changing it
A person has balance when the _____ falls within _______
Center of gravity
Base of support
A person has balance in the direct proportion to the _______
Size of the base
The ________ a base of support, the ______ balance
Larger
More
A person has balance depending on the _____
weight (mass)
The more _______, the _____ balance
Greater
More
A person has balance, depending on the _______ of the center of gravity
Height
The ________ the center of gravity, the ______ balance
Lower
More
A person has balance, depending on where the __________ is in relation to the ____________
Center of gravity
Base of support
Balance is less if the center of gravity is near the _______ of the base
Edge
In anticipation of an oncoming force, stability may be _________ by enlarging the size of the base of support in the direction of the anticipated force
Increased
__________ may be enhanced by _________ the friction between the body & the surfaces it contacts
Equilibrium
Increasing
________ about an axis aids balance
Rotation (moving bike is easier to balance than a stationary bike)
_________ _______ functions contribute to balance
Kinesthetic physiological (sight, touch, sense)
