ANGULAR KINETIC Flashcards
angular equivalent of newton first law
: The angular momentum of an object remains constant unless a net external torque is exerted on it
the change of angular momentum is porportional to what and in the direction of
net external torque and in the direction of this external torque
what happen if the external torque acting on an object do not sum 0
the object will experience an angular acceleration in the direction of the net torque. Its angular velocity will speed up or slow down, or its axis of rotation will change direction.
. If an object’s angular velocity or axis of rotation changes what need to be acting on the object to cause the angular acceleration
net external torque
the effect of the torque depent on what
moment of inertia of the object
what is inertia
: resistance of a system to having its state of motion changed by application of a force.
in linear kinetic inertia is what
mass, It is more difficult to speed up, slow down, or change the direction of a more massive object because it has more linear inertia
in angular kinetic inertia is
moment of inertia
moment of inertia depends on
mass, mass distribution, axis of rotation
What factors affect the angular inertia of an object?
mass of an object and mass distribution relative to the axis of rotation
can object have more than one angular inertia
yes
The sum of all the particles’ resistances to rotation is the
total moment of inertia of the object
what is a radius of gyration
length measurement that represents how far from the axis of rotation all of the object’s mass must be concentrated to create the same resistance to change in angular motion as the object had in its original shape.
what is an eccentric axis
An eccentric axis is one that does not pass through the implement’s center of gravity
if the mass of the implement is farther from the axis of rotation the moment of inertia increase or decrease
increase
what is the most efficient way to move the human body
maximize acceleration while minimizing torque requirements.
The longer radius of rotation of the striking surface of an implement causes a (larger/smaller) linear velocity at the striking end of the implement if the angular velocity is the same as the angular velocity of a shorter implement
larger
conservation of angular moment is what
There can be no change in momentum without an externally applied force.
linear momentum depend on what
velocity
angular momentum for non rigid obkect depend on what
moment of inertia and angular velocity
angular momentum for rigid objet depend on
only angular velocity
increase in moment of inertia cause what in angular velocity to keep angular momentum constant
decrease angular velocity a
since angular momentum always remain constant how can an athlete change their angular velocities
changing their moment of inertia
can an rigid object have many different moment of inertia
yes bc it may have many axis but each axis only have one moment of inertia associated with it
does a human moment of inertia about any axis is variable
yes, because human body are not rigid object
is it possible to accelerate without applied a torque
yes by changing moment of inertia
