Which of the following is not vector quantity ?

Options

A. Momentum
B. Weight
C. Potential energy
D. Nuclear spin

Answer

To determine which of the following quantities is not a vector quantity, we need to understand the definitions and characteristics of vector and scalar quantities.

### Step-by-Step Solution:

1. **Understanding Vector Quantities**:
- A vector quantity is defined as a physical quantity that has both magnitude and direction. Examples include displacement, velocity, acceleration, momentum, and force.

2. **Analyzing the Given Quantities**:
- **Momentum (P)**: Defined as the product of mass (m) and velocity (v). Since velocity is a vector, momentum is also a vector quantity.
- **Weight**: Weight is the force exerted by gravity on an object. Since force is a vector quantity, weight is also a vector quantity.
- **Nuclear Spin**: This quantity has both magnitude and direction (it can be positive or negative). Therefore, nuclear spin is also a vector quantity.
- **Potential Energy**: Defined as the work done against a conservative force. Work is defined as the dot product of force and displacement, which results in a scalar quantity. Since potential energy is derived from work, it is also a scalar quantity.

3. **Conclusion**:
- Among the quantities analyzed, potential energy is the only one that does not possess both magnitude and direction. Therefore, it is not a vector quantity.

### Final Answer:
The quantity that is not a vector quantity is **Potential Energy**.

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