The Question is from neet-physics rotational-motion , and it was created by the author VENKATESWARARAO

Question

A spinning ice skater pulls her arms inwards. What happens to her angular momentum?

VENKATESWARARAO · Accepted Answer

## CORE INFORMATION
✓ **Answer**: [C]
## CONCEPT FRAMEWORK
	**Primary Concept**: Conservation of Angular Momentum
	**Related Topics**: Rotational Motion, Moment of Inertia
	**Prerequisites**: Understanding of angular momentum and its conservation.
## SOLUTION PATHWAY
**Given Information**:
	* A spinning ice skater pulls her arms inwards.
	* No external torques are acting on the skater.
**Method & Steps**:
	1. **Identify the relevant principle**: Angular momentum is conserved in the absence of external torques.
		Reasoning: The skater is isolated, and there's no external force causing a torque.
		Formula/Rule: $L = Iω$ where L is angular momentum, I is moment of inertia and ω is angular velocity.
	2. **Apply the principle**: Since angular momentum is conserved, it remains constant.
		Working: When the skater pulls her arms in, her moment of inertia (I) decreases because mass is brought closer to the axis of rotation. To keep angular momentum (L) constant, angular velocity (ω) increases. However, the product $Iω$ remains constant.
	3. **State the conclusion**: Angular momentum remains constant.
		Result: The angular momentum of the skater remains constant.
		Verification: This aligns with the principle of conservation of angular momentum.
## OPTION ANALYSIS
[A] :x: Increases: This would imply an external torque, which is not the case.
[B] :x: Decreases: This would imply an external torque removing angular momentum, which is not the case.
[C] ✓: Remains constant: This is correct as angular momentum is conserved.
[D] :x: Becomes zero: This would require a complete stop of rotation, which is not happening.
## LEARNING AIDS
	**Common Mistakes**:
		1. [Error 1]: Confusing angular momentum with angular velocity. While angular velocity changes, angular momentum is conserved.
		2. [Error 2]: Assuming that pulling arms inwards changes angular momentum, rather than redistributing it.
	**Quick Tips**:
		1. [Helpful shortcut]: Remember that for an isolated system, angular momentum is always conserved unless an external torque acts upon it.
		2. [Memory aid]: Think of a figure skater spinning; they speed up when they pull their arms in, but their total angular momentum stays the same.

VENKATESWARARAO · Answer

Increases

VENKATESWARARAO · Answer

Decreases

VENKATESWARARAO · Answer

The correct Option is "Remains constant"

VENKATESWARARAO · Answer

Becomes zero

NEET Physics Systems Of Particles And Rotational Motion MCQs

Select Topic

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

NEET Subjects

Our Bots

Company