The angle made by the resultant of normal reaction and limiting value of frictional force with normal to the surface is called

Options

A. Angle of repose
B. Angle of friction
C. Critical angle
D. none of the above

Answer

To solve the question, we need to understand the forces acting on a body resting on a surface and how they relate to each other. Here's the step-by-step solution:

### Step 1: Identify the Forces Acting on the Body
When a body is resting on a surface, two primary forces act on it:
- The **normal reaction force (N)**, which acts perpendicular to the surface.
- The **frictional force (F)**, which acts parallel to the surface.

### Step 2: Understand the Limiting Value of Friction
The limiting value of friction is the maximum frictional force that can act on the body before it starts to move. It is denoted as \( F_{\text{lim}} \).

### Step 3: Determine the Resultant Force
The resultant force is the vector sum of the normal reaction force and the limiting frictional force. If we consider the normal force acting vertically upward and the frictional force acting horizontally, the resultant force will be at an angle to the normal.

### Step 4: Define the Angle with Respect to the Normal
The angle formed between the resultant of the normal reaction and the limiting value of the frictional force with respect to the normal (perpendicular to the surface) is what we are interested in.

### Step 5: Conclude the Definition
This angle is known as the **angle of friction**. It is denoted by \( \theta \) and is a measure of how much the frictional force can resist the motion of the body before it begins to slide.

### Final Answer
The angle made by the resultant of the normal reaction and the limiting value of frictional force with the normal to the surface is called the **angle of friction**.

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