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 solve the problem of calculating 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 (d) = 2 meters
- Resisting force (F) = 25 N

2. **Understanding Work Done by a Force:**
- The work done (W) by a force is given by the formula:
\[ W = F \cdot d \cdot \cos(\theta) \]
where \( F \) is the force, \( d \) is the displacement, and \( \theta \) is the angle between the force and the direction of displacement.

3. **Determine the Angle:**
- In this case, the resisting force acts in the opposite direction to the displacement. Therefore, the angle \( \theta \) is 180 degrees.

4. **Calculate the Cosine of the Angle:**
- The cosine of 180 degrees is:
\[ \cos(180^\circ) = -1 \]

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

6. **Calculate the Work Done:**
- Performing the multiplication:
\[ W = -50 \, \text{J} \]

7. **Conclusion:**
- The work done by the resisting force is:
\[ W = -50 \, \text{J} \]

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

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