A particle of mass `m` is moving along the line `y=b,z=0` with constant speed `v`. State whether the angular momentum of particle about origin is increasing, decreasing or constant.

Explanation

To determine whether the angular momentum of a particle moving along the line \( y = b, z = 0 \) with constant speed \( v \) about the origin is increasing, decreasing, or constant, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Motion**:
- The particle is moving along the line \( y = b \) in the \( xy \)-plane, which means its \( z \)-coordinate is always \( 0 \). The position of the particle can be represented as \( (x, b, 0) \).

2. **Defining Angular Momentum**:
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