A particle of mass m is projected with a velocity `v` at an angle of `theta` with horizontal. The angular momentum of the particle at the highest point of its trajectory is equal to :

Explanation

To find the angular momentum of a particle projected at an angle \(\theta\) with respect to the horizontal at the highest point of its trajectory, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Components of Velocity**:
- The initial velocity \(v\) can be broken down into its horizontal and vertical components.
- The horizontal component \(v_x\) is given by:
\[
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