Transcript Rotational Motion Powerpoint

Rotational Motion
Deg, Rad, Grad
There are 360 degrees in one rotation of a circe.
There are 2π radians in one rotation of a circle.
There are 400 gradians in one rotation of a circle.
Convert between radians and degrees to fill in the missing measurements below.
Angular Displacement, Velocity, and Acceleration.
Angular Displacement (θ): The change in angle (in radians) of a rotating object.
Angular Velocity (ω): The rate at which an object is spinning. Rad/s
Angular Acceleration (α): The rate at which a spinning object is changing speed.
Rad/s2
a  r 
ArcLength  r 
A Couple other useful formulas.
Rotational Dynamics & Torque
Lever Arm: The perpendicular
distance from the axis of rotation
to the point where the force is
exerted.
Torque: A measure of how
effective a force causes rotation.
Torque = Force perpendicular to
rotation times distance away
from the center of rotation.
Measured in N·m
  F r
Also seen as
  F  r sin 
when the force is not applied at a
right angle to the lever arm.
Label each of the situations in rows a and
having ‘No’, ‘Little’, or ‘Maximum’ effect.
b
as
The lug nut on your car needs to be torqued to 81.0 N·m. You have a wrench that is 25.0
cm long and you push at the angle indicated in the picture. With what force do you need
to push to correctly torque the nut?
Moment of Inertia
Moment of Inertia: Resistance to rotation
Moments of Inertia for Various Objects
Center of Mass – the point at which the entire mass of a body may be
considered concentrated.
Equilibrium: 1) Sum of all forces equals zero. 2) Sum of all torques equals zero.