In introductory physics, what is the SI unit of linear momentum?

• A. $N\cdot m$
• B. $kg\cdot \frac{m}{s}$
• C. $kg\cdot m^2\cdot s^{-2}$
• D. $kg\cdot m^2$

Answer: (B)

Verified step by step guidance

1. Recall that linear momentum \( \vec{p} \) is defined as the product of an object's mass \( m \) and its velocity \( \vec{v} \), so \( \vec{p} = m \vec{v} \).
2. Identify the SI unit of mass, which is the kilogram (kg).
3. Identify the SI unit of velocity, which is meters per second (m/s).
4. Since momentum is mass times velocity, multiply the units: \( \text{kg} \times \frac{\text{m}}{\text{s}} \).
5. Therefore, the SI unit of linear momentum is kilogram meter per second, written as \( \text{kg} \cdot \frac{\text{m}}{\text{s}} \).