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## Homework Statement

A uniform rod has a mass 2m and a length l, and it can spin freely in a horizontal plane about a pivot point O at the center of the rod. A piece of clay with mass m and velocity v hits

one end of the rod, and causes the rod-clay system to spin.

After the collisions the rod and clay system

has an angular velocity omega about the pivot.

Which quantity/quantities:

I) total mechanical energy

II) total linear momentum

III) total angular momentum with respect to pivot point O

IV) total gravitational potential energy

V) total kinetic energy

is/are conserved in this process?

Possible solutions:

1. III and IV only

2. II and III only - tried, was wrong

3. II, III, IV and V only

4. II, III and IV only

5. II and V only

6. I, II and III only

7. I only

8. None of these

9. III, IV and V only

10. All of these

## The Attempt at a Solution

I tried II and III only as a solution, but it was wrong. I'm thinking that mechanical energy, kinetic energy, and gravitational potential energy are not conserved due to the introduction of a piece of clay, but it seems I'm wrong in some area. Can anyone help point me in the right direction?