Principles of Motion and Stability Flashcards
to move yourself or objects, we must _
produce a force
- a stationary person or object will not move until some force is applied to it
Define Newton’s first law
an object at rest stays at rest, or an object in motion stays in motion, until acted on by a force
list the main takeaways of newton’s first law
- if an objects is at rest it requires an unbalanced force to make it not be at rest
- if an object is in motion, it tends to stay in motion in a straight line at a constant velocity unless an unbalanced force acts on it
definen unbalanced forces
- whenever one player exerts a force on another and causes them to change their direction and/or speed
define inertia
someone’s natural resistance to an unbalanced force
- more mass = more inertia
- mass DOES NOT EQUAL WEIGHT
differentiate between mass and weight
mass = a measure of how much matter an object hass (your mass is the same on space and earth)
weight = a measure of how strongly an object’s mass is attracted by gravity (you will have a lighter weight in space)
define newton’s second law
the acceleration of a person or object is proportional to the force applied to it and inversely proportional to its mass
list the main takeaways from the newton’s second law football example
in order for an object like a football to accelerate, a force must be applied
define impulse
a certain amount of force you apply for a certain amount of time to cause a change in momentum
impulse = force x time the force is applied
impulse = f(delta t)
define newton’s third law
the law of action-reaction, states that for every force you exert on an object, the object exerts and equal force back on you in the opposite direction
list the main takeaways for newton’s third law
- action-reaction law
- momentum
- conservation of momentum
define momentum
in football, the mass of a player x his velocity
P = MV
(p=momentum, m=mass, v=velocity)
define conservation of momentum
the total momentum between players must be the same before the collusion as it is after the collision
Pbefore = Pafter
eg. newton’s cradle
describe oppositional arm and leg movement in early stages of walking
- eventually, need a backward push for forward propulsion
- toddlers typically do not push down
- no oppositional arm movement yet
*most start to walk between 10-16 months
how does oppositional arm and leg movement in later toddlerhood*actual stage not on slides
- still no oppositional arm movements yet
- walk with wide base of support
- holding arms up to help with balance
as our oppositional arm and leg movement improves, start to see_
oppositional arm and leg movements developing
- toddlers cruising with better oppositional movements
ultimate example - runner (great arm and leg oppositional movements)
