1. By: Amy Rykaczewski and Lorraine Sacro

2.  An object rotating about an axis tends to keep rotating about that axis.  “A resistance to change of motion” –Kenneth Mellendorf

3.  A torque is required to change the rotational state of motion of an object  If there is no net torque, a rotating top keeps rotating, while a non-rotating top stays non- rotating

4.  Rotational inertia depends on mass  Depends on the distribution of mass  The greater the distance between the masses of an object the greater the rotational inertia  Ex: A long baseball bat has more inertia vs. a short baseball bat ▪ Rotates off the axis

5.  Rotational inertia is greater when the mass within the object is extended from the axis of rotation

6.  I = mr²  I = Inertia  m = mass  r = radius

8.  Rolling  An object that has less inertia will roll with a faster acceleration than an object with greater inertia

9.  A heavy iron cylinder and a light wooden cylinder, similar in shape, roll down an incline. Which will have more acceleration?

10.  The cylinders have different masses, but the same rotational inertia per mass, so both will accelerate equally down the incline. Their different masses make no difference, just as the acceleration of free fall is not affected by different masses. All objects of the same shape have the same “laziness per mass” ratio.