What is defined as the force required to give a mass of 1 kg an acceleration of 1 m/s²?

The force required to give a mass of 1 kilogram an acceleration of 1 meter per second squared is defined as a Newton. This unit is derived from Newton's second law of motion, which states that force equals mass times acceleration (F = m × a).

In this context, if you take a mass of 1 kg and apply an acceleration of 1 m/s², the calculation for force would be:

F = 1 kg × 1 m/s² = 1 N (Newton).

Therefore, the Newton is the standard unit of force in the International System of Units (SI), and this definition encapsulates the relationship between mass, acceleration, and force.

The other options refer to different physical quantities: a kilogram is a unit of mass, a pound is a unit of force used in some systems, and a Joule is a unit of energy. None of these alternative choices correctly represent the specific definition tied to the force applied to a mass in the context given.