A child is sitting on a merry-go-round that is rotating. If the child moves towa
Practice Questions
Q1
A child is sitting on a merry-go-round that is rotating. If the child moves towards the center, what happens to the rotational speed of the merry-go-round?
Increases
Decreases
Remains the same
Becomes zero
Questions & Step-by-Step Solutions
A child is sitting on a merry-go-round that is rotating. If the child moves towards the center, what happens to the rotational speed of the merry-go-round?
Correct Answer: Rotational speed increases
Step 1: Understand that a merry-go-round is rotating and has a certain speed.
Step 2: Know that the child sitting on the merry-go-round has mass and contributes to the overall mass distribution.
Step 3: Recognize that when the child moves towards the center, they are reducing the distance from the center of the merry-go-round.
Step 4: Realize that moving towards the center decreases the moment of inertia, which is a measure of how mass is distributed relative to the rotation axis.
Step 5: Remember the principle of conservation of angular momentum, which states that if no external torque acts on a system, its angular momentum remains constant.
Step 6: Since the moment of inertia decreases when the child moves towards the center, the rotational speed must increase to keep the angular momentum constant.
Angular Momentum Conservation – The principle that the total angular momentum of a closed system remains constant if no external torques act on it.
Moment of Inertia – A measure of an object's resistance to changes in its rotation, which depends on the mass distribution relative to the axis of rotation.
Rotational Speed – The rate at which an object rotates, often measured in radians per second or revolutions per minute.
