Question

a rod is at rest. a piece of clay collides with the edge of it and sticks, so they rotate together counterclockwise around the frictionless axle at the other edge. how does the angular momentum of the rod (not the rod-clay system) change as the clay collides?

Answer 1

The angular momentum of the rod changes as the clay collides and sticks to it. The initial angular momentum of the rod is zero but it increases when the rod starts rotating with the clay.

Step-by-step explanation:

When the piece of clay collides with the rod, it sticks to it and they rotate together counterclockwise around the frictionless axle. As a result, the angular momentum of the rod changes. The initial angular momentum of the rod is zero since it is at rest. However, when the clay sticks to the rod and they start rotating together, the angular momentum of the rod increases. This increase in angular momentum is due to the fact that the rod now has rotational motion.

Answer 2

The angular momentum of the rod increases as the clay collides and sticks to it, but the total angular momentum of the rod-clay system is conserved.

Step-by-step explanation:

The question asks how the angular momentum of a rod changes as a piece of clay collides with it at one end and sticks, causing the system to rotate counterclockwise around a frictionless axle located at the other end. According to the conservation of angular momentum, the total angular momentum of a system must remain constant if no external torques act on it. Prior to the collision, the rod is at rest, so its angular momentum is zero. As the clay collides and sticks to the rod, it exerts a force on the rod, causing the rod to rotate and thereby increasing its angular momentum. However, the total angular momentum of the rod-clay system is conserved, so the increase in angular momentum of the rod is equal to the initial angular momentum the clay had before colliding with the rod.