Question

A pendulum consists of a uniform disk with radius 10 cm and mass 500 g attached to a uniform rod with length 500 mm and mass 250.
Calculate the rotational inertia of the pendulum about the pivot point.

Answer 1

0.205 kg m^2

Answer 2

but how did you find it?

Answer 3

A uniform disk pivoted at its center has a rotational inertia of
1 2
2 Mr
, where M
is its mass and r is its radius. The disk of this problem rotates about a point that is
displaced from its center by r + L, where L is the length of the rod, so, according
to the parallel-axis theorem, its rotational inertia is
1 1 2 2
2 2 Mr M L r   ( )
. The rod is
pivoted at one end and has a rotational inertia of mL2
/3, where m is its mass. The
total rotational inertia of the disk and rod is6 | P a g e 2 2 2
2 2 2
2
1 1 ( )
2 3
1 1 (0.500 kg)(0.100 m) (0.500 kg)(0.500 m 0.100 m) (0.270 kg)(0.500 m)
2 3
0.205 kg m .

Answer 4

http://www.uh.edu/~wkchu/courses/OLD/004/5159/homeworksolutions15.pdf

Answer 5

6. Chapter 15, Problem 41

Answer 6

oh lol that's my book ok thanks a lot

Answer 7

u are welcome

Answer 8

yeah sure i was just reading the response