Unit 5 - Rotation, Energy, Work & Momentum Flashcards
angular displacement
the change in the angle as an object rotates
theta = s/r
angular velocity
The angular displacement of an object divided by the time needed to make the displacement.
omega = delta(theta/delta(t)
angular acceleration
change in rate of rotation
alpha = delta(omega)/delta(t)
moment of inertia
the resistance to rotation
I=Emr^2
angular momentum
the quantity of rotation of a body, which is the product of its moment of inertia and its angular velocity.
torque
a turning or twisting force
collision
A situation in which two objects in close contact exchange energy and momentum
elastic collision
one in which there is no net loss of total kinetic energy
inelastic collision
a type of collision in which the kinetic energy after the collision is less than the kinetic energy before the collision
Momentum
The product of an object’s mass and velocity
p=mv
Impulse Momentum Theory
states that the impulse on an object equals the object’s final momentum minus the object’s initial momentum
Fdelta(t)=mdelta(v)
^ Impulse ^Change in momentum
Impulse approixmation
reasonably neglecting small forces during the brief time of the impulsive force
Internal forces
a force that acts on an object from the inside
External forces
forces that act on an object as a result of its interaction with the environment surrounding it
Isolated system
A system that can exchange neither energy nor matter with its surroundings.
Law of Conservation of Energy
the law that states that energy cannot be created or destroyed but can be changed from one form to another
Law of Conservation of Momentum
law stating that the total momentum of a system does not change if no net force acts on the system
Kinetic energy
energy of motion
KE=1/2mv^2
Potential energy
stored energy
Elastic potential energy
the energy of stretched or compressed objects
Gravitational potential energy
Potential energy that depends on the height of an object
Mechanical energy
Kinetic or potential energy associated with the motion or position of an object
conservative force
a force that does the same work for any given initial and final configuration, regardless of the path followed
KEi+PEi+Wnc=KEf+PEf
Wnc= deltaE
non-conservative forces
forces that do work in such a manner that thermal energy is involved and mechanical energy is not conserved. examples are friction and fluid resistance along with horizontal pushing or pulling forces
work
Fd
forcexdistance
work-energy theorem
the theorem that states that whenever work is done, energy changes. W = Δ KE
Power
the rate at which work is done
