If `mu,R` and S represent coefficient of friction, normal reaction and distance moved, then the general expression for work against friction

Options

A. `mu` RS
B. `mu + R//S`
C. `mu R//S`
D. `mu S//R`

Answer

To derive the general expression for work done against friction, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components**:
- Let \( \mu \) be the coefficient of friction.
- Let \( R \) be the normal reaction force.
- Let \( S \) be the distance moved.

2. **Identify the Force of Friction**:
- The force of friction \( F \) can be expressed as:
\[ F = \mu R \]
This equation states that the frictional force is proportional to the normal force and the coefficient of friction.

3. **Calculate Work Done Against Friction**:
- Work done \( W \) against friction is given by the formula:
\[ W = F \times S \]
where \( F \) is the force of friction and \( S \) is the distance moved.

4. **Substitute the Expression for Friction**:
- Now, substituting \( F = \mu R \) into the work equation:
\[ W = (\mu R) \times S \]

5. **Final Expression**:
- Therefore, the general expression for work done against friction becomes:
\[ W = \mu R S \]

### Final Answer:
The general expression for work done against friction is:
\[ W = \mu R S \]