Two forces of magnitude 3N and 4N respectively are acting on a body. Calculate the resultant force if the angle between them is
`0^(@)`

Explanation

To calculate the resultant force when two forces of magnitudes 3N and 4N are acting on a body at an angle of 0 degrees, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Forces**:
- Let \( F_1 = 3 \, \text{N} \) (the first force)
- Let \( F_2 = 4 \, \text{N} \) (the second force)

2. **Understand the Angle**:
- The angle \( \theta \) between the two forces is given as \( 0^\circ \).

3. **Use the Formula for Resultant Force**:
- The formula to calculate the resultant force \( R \) when two forces are acting at an angle \( \theta \) is:
\[ R = \sqrt{F_1^2 + F_2^2 + 2 F_1 F_2 \cos(\theta)} \]

4. **Substitute the Values**:
- Since \( \theta = 0^\circ \), we know that \( \cos(0^\circ) = 1 \).
- Substitute the values into the formula:
\[ R = \sqrt{(3)^2 + (4)^2 + 2 \cdot 3 \cdot 4 \cdot 1} \]

5. **Calculate Each Term**:
- Calculate \( (3)^2 = 9 \)
- Calculate \( (4)^2 = 16 \)
- Calculate \( 2 \cdot 3 \cdot 4 \cdot 1 = 24 \)

6. **Combine the Results**:
- Now combine these results:
\[ R = \sqrt{9 + 16 + 24} \]
\[ R = \sqrt{49} \]

7. **Final Calculation**:
- Calculate the square root:
\[ R = 7 \, \text{N} \]

### Conclusion:
The resultant force when the angle between the two forces is \( 0^\circ \) is \( 7 \, \text{N} \).