Equivalent to force in rotational motion is

Options

A. moment of force
B. impulse
C. moment of inertia
D. none of these

Answer

To solve the question "Equivalent to force in rotational motion is," we need to understand the concept of rotational dynamics and the terms associated with it.

### Step-by-Step Solution:

1. **Understanding Force in Linear Motion**:
- In linear motion, force is defined as the interaction that causes an object to change its velocity. It is measured in Newtons (N).

2. **Identifying the Equivalent in Rotational Motion**:
- In rotational motion, the equivalent of force is known as "torque" or "moment of force." Torque is the measure of the force that can cause an object to rotate about an axis.

3. **Definition of Torque**:
- Torque (τ) is defined mathematically as:
\[ τ = r \times F \]
where:
- \( τ \) is the torque,
- \( r \) is the distance from the pivot point to the point of force application (lever arm),
- \( F \) is the applied force.

4. **Understanding the Tendency to Rotate**:
- Torque represents the tendency of a force to cause an object to rotate about a pivot point. The greater the torque, the greater the tendency of the object to rotate.

5. **Moment of Inertia**:
- Another important concept in rotational motion is the moment of inertia (I), which is the rotational analog of mass in linear motion. It depends on the mass distribution of the object relative to the axis of rotation.

6. **Conclusion**:
- Therefore, the equivalent to force in rotational motion is **torque** (or moment of force).

### Final Answer:
The equivalent to force in rotational motion is **torque** (or moment of force).

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