Units and dimensions – SI unit of force Identify the correct SI (International System of Units) unit for force used in engineering mechanics.

Introduction / Context:
Consistent units are essential in calculations. Force has a specific SI unit tied directly to Newton’s second law, linking mass, acceleration, and force.

Given Data / Assumptions:

• SI base units: kilogram (kg), meter (m), second (s).
• Force defined via F = m * a.

Concept / Approach:
In SI, the unit of force is the newton (N), defined as the force required to accelerate a mass of 1 kg at 1 m/s^2, so 1 N = 1 kg·m/s^2.

Step-by-Step Solution:

Verification / Alternative check:
Compare with other systems: in the cgs system, the unit of force is the dyne where 1 dyne = 1 g·cm/s^2 = 10^-5 N, confirming that dyne is not the SI unit.

Why Other Options Are Wrong:

• dyne: cgs unit, not SI.
• kilogram: SI base unit of mass, not force.
• watt: SI unit of power (J/s), not force.

Common Pitfalls:
Mixing cgs and SI units in the same problem leads to magnitude errors by factors of 10^n.

Final Answer:
newton