Impulse is

Options

A. a scalar quantity
B. a vector quantity
C. neigher a scalar nor a vector
D. sometimes a scalar and sometimes a vector

Answer

To solve the question "Impulse is:", we need to determine whether impulse is a scalar quantity, a vector quantity, neither, or sometimes one and sometimes the other.

### Step-by-Step Solution:

1. **Understanding Impulse**:
- Impulse is defined as the change in momentum of an object when a force is applied over a period of time.

2. **Formula for Impulse**:
- The formula for impulse (J) can be expressed as:
\[ J = \Delta p = F \cdot \Delta t \]
where \( \Delta p \) is the change in momentum, \( F \) is the force applied, and \( \Delta t \) is the time duration over which the force is applied.

3. **Analyzing Momentum**:
- Momentum (p) is defined as the product of mass (m) and velocity (v):
\[ p = mv \]
- Since both mass and velocity are vector quantities, momentum is also a vector quantity.

4. **Change in Momentum**:
- The change in momentum (\( \Delta p \)) is also a vector quantity because it is derived from the vector quantities of mass and velocity.

5. **Conclusion on Impulse**:
- Since impulse is defined as the change in momentum, and change in momentum is a vector quantity, it follows that impulse is also a vector quantity.

6. **Final Answer**:
- Therefore, the correct answer to the question "Impulse is:" is **option 2: a vector quantity**.