Question

Js is the unit of …….. physical quantity.

Hint:

Angular momentum is the rotational analog of linear momentum. It is given by \( L = I\omega \) and has the SI unit joule-second (Js).

Answer 1

Step 1: Understanding the Unit of Angular Momentum 
The joule-second (Js) is the SI unit of angular momentum, which is a measure of rotational motion. 
Step 2: Formula for Angular Momentum 
Angular momentum (\( L \)) is defined as: \[ L = I \omega \] where:
- \( I \) is the moment of inertia (\( kg \cdot m^2 \)),
- \( \omega \) is the angular velocity (\( rad/s \)). From the above relation: \[ L = (kg \cdot m^2) \times (rad/s) = kg \cdot m^2 /s \] which is equivalent to Js (joule-second). 
Step 3: Physical Meaning 
- Angular momentum represents the rotational equivalent of linear momentum.
- It is a conserved quantity, meaning that in the absence of external torque, the total angular momentum of a system remains constant. 
Step 4: Conclusion 
Since angular momentum has the unit Js, the correct answer is Angular Momentum.