A particle of mass `m` is projected from origin `O` with speed `u` at an angle `theta` with positive x-axis. Positive y-axis is in vertically upward. Direction. Find the angular momentum of particle at any time `t` about `O` before the particle strikes the ground again.

Explanation

To find the angular momentum of a particle of mass `m` projected from the origin `O` with speed `u` at an angle `theta` with the positive x-axis at any time `t`, we can follow these steps:

### Step 1: Determine the position and velocity of the particle at time `t`
The initial velocity components of the particle can be expressed as:
- Horizontal component: \( V_{x} = u \cos(\theta) \)
- Vertical component: \( V_{y} = u \sin(\theta) - gt \) (where \( g \) is the acceleration due to gravity)

The position of the particle at time `t` can be calculated using the equations of motion:
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