Sunday

April 20, 2014

April 20, 2014

Posted by **susane** on Saturday, December 9, 2006 at 7:19pm.

work:

I know that

I= mr^2

I=(2.0kg)(1.0m)^2

I=2 kgm^2 for one body

for 4 x 2.=8

so I figured if is a rigid body all the mass would count for the Y axis array, I am not sure.

Consider four objects, each having the same mass and radius

1) a solid sphere

2) a hollow sphere

3) a flat disk in the x,y plane

4) a hoop in x,y plane

The order of increasing rotational inertia about an axis through the center of mass and parallel to the z axis.

Work:

I know that rotational inertia is smaller when mass is closer to the axis so I throught

1, solid sphere has mass distributed close to axis

3) a flask disk would have a mass closely ditributed to its axis

2) a hollow sphere would have points where the mass was distributed close to the axis near the top

4) the hoop contains only a ring of mass and may not be near the axis.

The first is right, if the rotational axis is the z axis, perpendicular to the xy plane. But about the y axis, you only have the two x masses rotating.

I would reverse 2,3 on inertia. The hollow sphere will have more near the axis than the flat disk.

**Related Questions**

Physics - The rigid object shown in Fig. 10-63 consists of three balls and three...

Math Help Please - Can you Please explain the answer that I received of 2469? It...

physics - blocks 1 and 2 of masses 2 kg and 4kg, respectively, are connected by ...

Physics 203 ( College) - Four particles, one at each of the four corners of a ...

Physics - Cn u xplain the solutions steps by steps? Cz i really dnt understand ...

Physics - Two identical masses are connected by a (massless, stretchless) string...

Math - Received answer to the following question from Jishka. (2469) Would you ...

physics - Four masses are arranged as shown. They are connected by rigid, ...

MATH - Need Answer to the Following Please: Using the 9 digits, 1, 2, 3, 4, 5, ...

Math - Using the 9 digits, 1, 2, 3, 4, 5, 6,7, 8 and 9 you can arrange four ...