Test Two Angular Motion Flashcards
does pure linear motion really exist
no
what is rotation
moving around a fixed axis
what is a radian
distance around circle to have the same amount as radius
2pi radian equals what in degrees
360
1 radian pi =
180
how much is one revolution
2 pi radius
angular motion requires a
torque
linear motion requires a
force
what is torque
tendency of an eccentric force to rotate an object around an axis
you can increase torque by increasing
force, radius, or angle at which the force acts relative to the horizontal axis
what is the moment arm
perpendicular distance between the axis of rotation and the line of action of the applied force
a longer moment arm provides
better leverage, allows same force to produce a larger moment/torque at the axis, bolt easier to turn
what happens in force applied at an angle of the moment arm
angle of application of force, reduce the size of the moment arm
what is a positive direction of torque
counterclockwise
what is the negative direction of torque
clockwise
determine net torque
find magnitude of force, find the length of the moment arm, calculate torque, est the direction of each torque, sum the torques to find the net magnitude and direction of rotation caused by the torques
torque and center of gravity
the point around which all of the torques sum to zero, only applies in vertical direction
what is angular displacement
change in angular position of a segment or any point on the rotating segment
angular displacement is measured in
degrees, radians, revolutions
angular velocity has units of
radians/sec, degrees/sec, revs/sec
what is tangential linear velocity
linear velocity of a point on a rotating segment
how to go from degrees to m/s
must convert degrees to radians and then radians/sec to m/s
what is angular acceleration
a change in magnitude and/or direction of the angular velocity vector with respect to time
what is rotational inertia
the resistance of an object to having its state of angular motion changed
what are factors of rotational inertia
mass and mass distribution
angular acceleration is directly proportional to
the net torque applied
angular acceleration is inversely proportional to
the rotational inertia of the segment being accelerated
tangential acceleration is equal to
angular acceleration x radius
centripetal acceleration is equal to
tangential velocity / radius
changes in angular momentum are the result of changes
in the radius of rotation (which changes the moment of inertia) or changes in angular velocity
changes in angular momentum are directly related to
Newton’s first two laws of motion
Principle of conservation of angular momentum
in the absence of externally applied torque the total angular momentum of a system comprised of multiple bodies remains constant in time
what happens with angular velocity when moment of inertia is being manipulated but you need to conserve angular momentum
velocity changes to conserved angular momentum
what is rotational work
the angular displacement of an object about an axis caused by the application of a torque
what is rotational power
the amount of angular mechanical work performed during a given interval
what is rotational KE
rotational inertia and its angular velocity
