Rotational dynamics Flashcards
(18 cards)
what is angular displacement, angular velocity and angular acceleration
angle through which a body has rotated (arc length)
rate of change of angular displacement (omega)
rate of change of angular velocity
what are the angular counterparts for suvat
s - angular displacement
u - angular velocity
v - final angular velocity
a - angular acceleration
t - time
torque definition
change in rotational motion due to a turning force
what is the torque of a couple
the sum of the moment s produced by each force
what is the moment of inertia
the resistance to a change in rotational motion
what does the moment of inertia depend on
the total mass
how the mass is distributed about the axis of rotation
why is the moment of inertia a sum
it is a summation of all moments of inertia for every particle in the body
what is the rotational equivalent to force and mass
torque and the moment of inertia
what is the rotational equivalent to momentum
angular momentum
what is the principle of angular momentum
angular momentum of a system remains constant unless acted on by a net torque
how is angular momentum always conserved in there is changing radius
bigger r means mr^2 is bigger
bigger r means v/r is smaller
therefore overall it remains constant
what is angular impulse
rate of change of angular momentum
when is work done an a rigid body
when a torque rotates it through an angle about an axis
what is frictional torque and its equation
torque caused by the friction between two object moving past each other
resultant torque = applied torque + frictional torque
frictional torque is negative when it is doing work against the system however positive when it is doing work for the system
what are the two equations for angular kinetic energy
= 1/2Iw^2
= angular momentum^2/2xmoment of inertia
when a object roles without slipping what are the difference in linear velocity
at bottom v= 0
at center v = wr
and top v = 2wr
what is total kinetic energy of a rolling object
liner kinetic + angular kinetic
what is a flywheel
why wheels rotational kinetic energy in order to supply energy when required, they have a very large moment of inertia.
