A block is pushed through 2m across is surface offering 25 N resistance. The work done by the resisting force

Options

A. `50`J
B. 25`J
C. `-50`J
D. `-25`J

Answer

To find the work done by the resisting force when a block is pushed across a surface, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Values**:
- Displacement (S) = 2 m
- Resisting Force (F) = 25 N

2. **Understand the Direction of Forces**:
- The block is pushed in one direction (let's say to the right), while the resisting force acts in the opposite direction (to the left).

3. **Use the Work Done Formula**:
- The work done (W) by a force is given by the formula:
\[ W = F \cdot S \cdot \cos(\theta) \]
- Where:
- \( F \) is the magnitude of the force,
- \( S \) is the displacement,
- \( \theta \) is the angle between the force and the direction of displacement.

4. **Determine the Angle**:
- Since the resisting force acts in the opposite direction to the displacement, the angle \( \theta \) is 180 degrees.

5. **Calculate the Cosine of the Angle**:
- \( \cos(180^\circ) = -1 \)

6. **Substitute the Values into the Formula**:
- Now substituting the values into the work done formula:
\[ W = F \cdot S \cdot \cos(180^\circ) = 25 \, \text{N} \cdot 2 \, \text{m} \cdot (-1) \]

7. **Perform the Calculation**:
- Calculate:
\[ W = 25 \cdot 2 \cdot (-1) = -50 \, \text{J} \]

8. **Conclusion**:
- The work done by the resisting force is \( -50 \, \text{J} \).

### Final Answer:
The work done by the resisting force is **-50 Joules**.

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