Torqued An investigation of rotational motion

Think Linearly Linear motion: we interpret – position as a point on a number line – velocity as the rate at which position increases – acceleration as the rate at which velocity increases

Angular Quantities Rotational motion: based on the radius of the rotating object and the number of revolutions it passes through, we can relate – position angle – angular velocity velocity – Angular acceleration acceleration For a disk of radius r: r # revolutions #angles in one revolution Name this formula! Linear distance

Torque Torque, T, occurs when forces do not occur at an object’s center of mass (balance point). – T=F*d, where F is a force and d is distance from center of mass Torque-angular acceleration: T=I*α Compare to Newton’s 2 nd law: F=m*a Torque is defined by the direction the load may rotate an object: – CCW is (+) – CW is (-) How do you think these disks will rotate?

Activity Purpose We will use weights to rotate the drive axle of our mousetrap cars. We can record the acceleration of the falling weight and compare this to the torque provided by the weight in order to calculate the Moment of Inertia of the axle.

Hypothesis **Think about these questions** Which type of axle will have a larger moment of inertia -- one with large wheels or one with small wheels? Do you think the mass of the axle assembly (axle + wheels) affects the moment of inertia more or less than its size?