define inertia
resistance of an object to motion
define mass
measurement of inertia (way to quantify)
how does mass distribution of a body segment affect rotational motion
if mass is farther from axis of rotation is will make it more difficult to cause motion of the segment
define moment of inertia
resistance of an object to angular motion - based on mass distribution about a given axis
define radius of gyration
distance from axis where mass is assumed to be concentrated without changing inertial properties
what is the difference between radius of gyration and center of mass?
radius of gyration depends on the axis of rotation and will change while center of mass is the even distribution of mass that does not depend on the axis of rotation
in regards to law of action/reaction what is true of forces ( or moments) and their effects
forces between two objects are equal and opposite, but their individual effects on each other are different!
define momentum and how it is measured
product of mass x velocity and is the quantity of motion possessed by a body
what is impulse
average force x time (equal to area under the force-time plot)
how are impulse and momentum related
impulse is equal to the change in momentum
based on the impulse-momentum relationship, how can we change momentum
manipulate the time the force is applied
on a horizontal ground reaction impulse while running what is occurring during the negative posterior directed impulse
heel hits the ground
on a horizontal ground reaction impulse while running what is occurring during the anterior-directed impulse
toes touch the ground
