A force of 50 N moves a body. Then,

Options

A. frictional force exerted on the body is less than 50 N.
B. Frictional force exerted on the body is more than 50 N.
C. both (a) and (b).
D. none of these.

Explanation

To solve the question, we need to analyze the scenario where a force of 50 N is applied to a body that is initially at rest. Let's break down the solution step by step.

### Step-by-Step Solution:

1. **Understanding the Situation**:
- A force of 50 N is applied to a body on a horizontal rough surface.
- The body was initially at rest and is now in motion due to the applied force.

**Hint**: Identify the forces acting on the body and their directions.

2. **Identifying Forces**:
- The applied force (F_applied) is 50 N to the right.
- There is a frictional force (F_friction) acting in the opposite direction (to the left) due to the rough surface.

**Hint**: Remember that friction opposes the motion of the body.

3. **Applying Newton's Second Law**:
- According to Newton's second law, the net external force (F_net) acting on the body is equal to the mass (m) of the body multiplied by its acceleration (a).
- The equation can be written as:
\[ F_{net} = F_{applied} - F_{friction} = m \cdot a \]

**Hint**: Think about how the net force relates to the acceleration of the body.

4. **Determining the Relationship Between Forces**:
- Since the body is accelerating to the right, the net force must be greater than zero. This means:
\[ F_{applied} > F_{friction} \]
- Given that \( F_{applied} = 50 \, N \), we can conclude:
\[ 50 \, N > F_{friction} \]

**Hint**: The body is moving, which implies that the applied force must overcome the frictional force.

5. **Conclusion**:
- From the analysis, we can conclude that the frictional force exerted by the body is less than 50 N.
- Therefore, the correct answer is that the frictional force exerted by the body is less than 50 N.

**Hint**: Review the options provided in the question to select the correct one based on your conclusion.

### Final Answer:
The frictional force exerted by the body is less than 50 N.