Rotational Inertia and the Parallel-Axis Theorem Pre-Lab

PurposeTo confirm:1.The rotational inertia of a disk can be calculated using the models derived in class.2.The rotational inertia about a parallel axis a perpendicular distance h from the center of mass can be found using the Parallel-Axis Theorem.

Rotational Inertia and the Parallel-Axis Theorem Pre-Lab

sinrF

pulley the of radius rstring the in TFF

90

TrF

r

The clamp-on Super Pulley must be adjusted at an angle, so that the thread

runs in a line tangent to the point where it leaves the 3-step Pulley and straight down the middle of the groove on the clamp-on

Super Pulley (Figure 1.2).

Rotational Inertia and the Parallel-Axis Theorem Pre-Lab

sinrF

pulley the of radius rstring the in TFF

90

TrF

gF

TF

Tg FF Since the masses are accelerating

downward.

yy amF

maFF gT

maFF gT

mamgFT

agmFT

Since the string doesn’t slip, the linear acceleration of the masses is equal to the tangential acceleration

of the outside of the pulley.

pulley the of masses the of taa

rat

a

find To

Rotational Inertia and the Parallel-Axis Theorem Pre-Lab

TrF agmFT rat

rgrm

Newton’s Second Law I

I

rgrmI

Experimental Rotational Inertia