A lorry carries a tank of water. If the lorry moves with a uniform acceleration 'a' in the horizontal direction, determine the angle made by the surface of water in the tank with the horizontal.

Explanation

To solve the problem of determining the angle made by the surface of water in a tank with the horizontal when the lorry is moving with a uniform acceleration 'a', we can follow these steps:

### Step 1: Understand the Forces Acting on the Water
When the lorry accelerates horizontally, the water in the tank experiences two forces:
1. The gravitational force acting downwards (weight of the water), which is \( mg \) (where \( m \) is the mass of the water and \( g \) is the acceleration due to gravity).
2. An inertial force acting horizontally in the opposite direction of the acceleration of the lorry, which is \( ma \) (where \( a \) is the acceleration of the lorry).

### Step 2: Set Up the Right Triangle
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