Force and mass are related by their opposite influence on acceleration: Force increases acceleration, whereas mass causes acceleration to decrease. Mass is a measure of resistance to acceleration and force is an interaction that causes acceleration, according to The Physics Hypertextbook. Both represent scientific entities acting on the rate of change in velocity of an object, defined as acceleration.

Acceleration is directly proportional to the net external force in a system, whereas it is inversely proportional to the mass of the same system, states OpenStax College. This proportionality is the basis for Newton’s second law of motion, defined by the mathematical equation F = ma, where F is force, m is mass and a is acceleration. The more mass an object contains, the greater the force required to cause that object to accelerate, or move a constant distance. The Physics Classroom explains Newton’s first law of motion, called the law of inertia, states that if the forces acting on an object are balanced, the object is at equilibrium and acceleration of the object is zero. Therefore, if an object is being pushed with the amount of force equal to the mass of the object, then the object will not move. The standard metric unit of force is one Newton, which is defined as the amount of force required to give one kilogram of mass an acceleration of one meter per second squared.