In the SI system, which combination of base units describes force (the newton, N)?

• A. $kg\cdot m\cdot s^{\mathrm{-1}}$
• B. $kg\cdot m\cdot s^{\mathrm{-2}}$
• C. $kg\cdot m^2\cdot s^{\mathrm{-2}}$
• D. $kg\cdot s^{\mathrm{-2}}$

Answer: (B)

Verified step by step guidance

1. Recall that force is defined by Newton's second law as \(F = m \times a\), where \(m\) is mass and \(a\) is acceleration.
2. Identify the SI base unit for mass, which is the kilogram (kg).
3. Identify the SI base units for acceleration. Acceleration is the rate of change of velocity with respect to time, so its units are meters per second squared, written as \(m \times s^{-2}\).
4. Combine the units for mass and acceleration to express force: \(\text{force unit} = kg \times m \times s^{-2}\).
5. Therefore, the newton (N), the SI unit of force, is expressed in base units as \(kg \cdot m \cdot s^{-2}\).