LECTURE #10 - linear kinetics Flashcards
what are the three laws of motion ?
LAW #1 - law of inertia
LAW #2 - law of acceleration
LAW #3 - law of reaction
what is the first law of motion ?
law of inertia
what is the second law of motion ?
law of acceleration
what is the third law of motion ?
law of reaction
what is law of inertia
objects @ rest stay at rest and objects moving stay moving (momentum)
what is the law of acceleration ?
the change of motion is proportional to the force impressed and is made in the direction of the straight line in which that force is impressed
“change of motion” is used to define what term ?
acceleration
if a net force is applied to an object then :
- object will accelerate in direction of net external force
- acceleration will be proportional to net external force & inversely proportional to its mass
what does proportional mean ?
one goes up and one goes down
when mass goes up what does it mean for acceleration ?
acceleration goes down (harder to move)
FILL IN THE BLANK
measure of force is the ________
newton
FILL IN THE BLANK using ↑ and ↓
__ motion : __ magnitude or __ duration
↑motion : ↑magnitude or ↑duration
FILL IN THE BLANK
_________ is the amount of force it takes to accelerate a 1-kg object 1 m/s^2
1 newton
N = what unit ?
1 kg * 1 m/s^2
TRUE OR FALSE
N = kgm/s^2
TRUE
what is the formula for law of acceleration ?
ΣF = ma
what does “ΣF” stand for ?
net external forces
what does “m” stand for ?
mass of object
what does “a” stand for ?
acceleration of object
define cause and effect relationships of law 2 :
- forces causes acceleration
- acceleration is the effect of forces
what is impulse ?
product of force and time over which force acts
FILL IN THE BLANK regarding impulse :
“when force is applied to a body, the resulting motion is dependent upon both the ___________ and _________ of force”
magnitude and duration
what is the formula for impulse :
impulse = __ x ___
impulse = (F) (t)
what are the units for impulse ?
(N)(s)
define impulse :
product of a force and the time interval over which the force acts
what two things do momentum changes rely on impulse ?
- magnitude of external force
- length of time over which external force acts
TRUE OR FALSE
for momentum, change will be directly placated on momentum ?
TRUE
the following is the formula for what ?
m(v(f) - v(i))
momentum (newtons second law restated)
TRUE OR FALSE
during impact situations, we often control impulse to produce the desired outcome ?
TRUE
FILL IN THE BLANK using ↑ and ↓
__ impulse = __ momentum = ___ jump hight
↑ impulse = ↑ momentum = ↑ jump high
to have a change in momentum what must we see ?
- change of state of motion
- increase time and abruptly stop (deceleration)
- force incorporated for how long its being applied for
define hard landing :
dissipating a large force over short time
define soft landing :
dissipating a large force over long time
what does GRF stand for ?
ground reaction force
“change in momentum” is defined by what term ?
impulse
what do we do to length to the amount of time to reduce force ?
lengthening the amount of time
______ & ______ = force
action & reaction
define the law of reaction
to every action theres always opposed an equal reaction: or, the mutual action of two bodies upon each other are always equal and directed to contrary parts
what are the 4 interpretations of law of reaction :
- forces never act in isolation, always in pairs
- forces are equal in magnitude
- forces are in opposite direction
- action (force) & reaction (counterforce) act on different objects
what is the first interpretation of the law of reaction ?
forces never act in isolation, always in pairs
what is the second interpretation of the law of reaction ?
forces are equal in magnitude
what is the third interpretation of the law of reaction ?
forces are in opposite direction
what is the fourth interpretation of the law of reaction ?
action (force) & reaction (counterforce) act on different objects
- don’t cancel each other out
- may have different effect on the object
what do GRF’s contribute to ?
contribute to overuse injuries such as stress fracture and to diseases such as osteoarthritis
