angular motion
refers to rotation and movement around a fixed point or axis
torque
newtons laws (angular)
moment of inertia
the rotational consequence of a force
force x perpendicular distance from the fulcrum
inertia
acceleration
a rotating body will continue to turn about the axis of rotation with a constant angular momentum unless torque is placed upon it
the greater the torque exerted, the faster rotation will be
action reaciton
when torque is applied by one body to another, the second body will exert an equal and opposite force on the other body
quantities used
angular displacement - the smallest change in angle between the start and finish point of a rotation measured in radian (1 radian = 57.3 degrees)
angular velocity - the rate of change of angular displacement angular velocity = angular displacement (rad) / time taken (s)
angular acceleration - the rate of change of angular velocity aa (rad/s2) = change in angular velocity (rad/s) / time taken
resistance of a body to angular motion
dependent on mass of the body and distribution of mass around the axis
mass
greater the mass = greater the resistance to change
distribution
closer the mass = the easier to turn due to low moment of inertia
further away the mass = larger moment of inertia
angular momentum
the quantity of rotation a body possesses
angular momentum (L) = moment of inertia x angular velocity
conservation of angular momentum
occurs in sport during flight or on ice/snow where there is little friction
happens when the athlete directly manipulates their inertia e.g. when a figure skater performs multiple spins