How is the magnitude of a force typically expressed?

The magnitude of a force is typically expressed in newtons or pounds because these units are defined specifically for measuring force in the International System of Units (SI) and in the Imperial system, respectively.

The newton is the SI unit of force, and it is defined as the amount of force required to accelerate a one-kilogram mass by one meter per second squared. This relationship is outlined in Newton's second law of motion, establishing a clear and consistent basis for measuring force in scientific contexts.

The pound, on the other hand, is used primarily in the United States and some other countries as a unit of force in the Imperial system, where it conveys the same concept of how much push or pull is applied to an object.

The other units mentioned—radians, joules, and liters—are not appropriate for expressing force. Radians are a unit of angular measurement, joules are units of energy, and liters measure volume. Therefore, expressing force in newtons or pounds clearly identifies it as a measurement of push or pull, which aligns with the definitions and principles established in physics.