Wk 4 - Linear Kinetics Flashcards
_______ is defined as any interaction, a push or pull b/w 2 objects
Force
______ is what causes something to move
Kinetics
______ describes how something moves
Kinematics
Are forces vector or scalar quantities?
Vector (both magnitude and direction)
Forces can ______ motion, ______ motion, ______ or ______ in direction
produce motion, stop motion, positive or negative acc or change in direction
Units of measurement for force is…?
Newton (N)
Vectors - use arrows: length indicates _____ of force
magnitude
Vectors - use arrows: arrow head indicates _____ of force
direction
magnitude =
Amount of force applied
straight line of infinite length in direction of acting force is the…?
Line of application
orientation of the line of application gives an ang position which is the …?
Angle of application
a force, velocity, or other vector quantity which is equivalent to the combined effect of two or more component vectors acting at the same point is called a …?
resultant
____ ____ is defined to compose or resolve in which there are multiple forces?
Force systems
Force systems acting in a single plane is called _____
coplanar
Force systems acting at a single point is called _____
Concurrent
Force system of vectors acting along a single line is called a _____
Collinear
Force system which breaks force into its components with respect to the coordinate system is called _____
the resolution
What is Newtons 1st Law?
The law of inertia
The law of inertia is…
‘A body will maintain a state of rest or constant velocity unless
acted on by an (a NET) external force that changes the state’ of
motion
Inertia is defined by…?
Reluctance to change state of rest or motion
The _____ the mass, the ____ the inertia = harder to move object
greater
Newtons 2nd Law is the …?
Law of acceleration
Any time you increase or decrease speed it is…?
Accelertion/deceleration
Force = ____ x ____
Force = mass x acceleration
Acceleration = ___ x ___
Acc = vel / time
______ is a quantity of motion of an object
momentum
p or m stand for
momentum
momentum (p) = ____ x ____
p = mass x vel
Newton’s 3rd law is …
The law of reaction
The law of reaction (3rd law) means…
For each action (force) there is an equal and opposite reaction (force)
What is a non contact force?
Acts at a distance, not directly in contact with each other (e.g. gravity)
Which law is this: ‘All bodies are attracted to one another with a force proportional to the product of their masses and inversely proportional to the distance between them’
The law of gravitation
What affects the law of gravitation ? (2)
Distance between the two and mass
The higher the altitude the _____ the gravity
Lower
Contact forces are
exerted by one object in direct contact with another object
The max vertical GRF in walking is …
1-1.3 of body weight
The max vertical GRF in running is…
3-5 body weight
______ is a contact force acting parallel to the interface of 2 surfaces
friction
Doe friction always oppose motion?
Yes
The objects not moving has friction preventing it from moving…
Static friction
The object is moving but there are still forces trying to oppose the motion
Max static friction
μ means…
the coefficient of friction
Once the object is sliding, the frictional force opposing it is ____ than what it was before it started moving
less
Friction can be change by …?
altering both surfaces
Is friction related to the area of contact?
No. only roughness
Can forces be present without motion?
Yes
