No work is said to have been done when an object moves at an angle of _____ with the direction of the force.

Options

A. `0^(@)`
B. `90^(@)`
C. `180^(@)`
D. between `90^(@) and 180^(@)`

Answer

To solve the question, "No work is said to have been done when an object moves at an angle of _____ with the direction of the force," we need to understand the relationship between work, force, and displacement.

### Step-by-Step Solution:

1. **Understanding Work Done**:
Work done (W) is defined as the product of the force (F) applied on an object and the displacement (s) of the object in the direction of the force. Mathematically, it is given by:
\[ W = F \cdot s \cdot \cos(\theta) \]
where \(\theta\) is the angle between the force and the direction of displacement.

2. **Identifying When Work is Zero**:
For work done to be zero, the cosine of the angle must be zero:
\[ \cos(\theta) = 0 \]
This occurs when \(\theta\) is 90 degrees, meaning the force is applied perpendicular to the direction of displacement.

3. **Conclusion**:
Therefore, no work is said to have been done when an object moves at an angle of **90 degrees** with the direction of the force.

### Final Answer:
No work is said to have been done when an object moves at an angle of **90 degrees** with the direction of the force.

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