Moment of force units from torque definition

Steps:

• Moment of a force is torque, τ = F × d, where F is force and d is perpendicular distance.
• SI unit of force F is newton, kg·m/s².
• SI unit of distance d is meter, m.
• Multiply units: (kg·m/s²) × m = kg·m²/s².

Why A is correct:

• Directly follows from torque formula τ = r × F, yielding kg·m²/s² as the SI unit.

Why the others are wrong:

• B: kg s² represents mass times time squared, unrelated to force or moment.
• C: kg m/s² is the unit for force alone, omitting the distance factor.
• D: kg m²/s is the unit for angular momentum, not moment of force.

Final answer: A