Newton's Second Law provides a relationship between the unbalanced force on the object, the mass of the object and the acceleration that is produced: unbalanced force = mass x acceleration or F = ma. The unbalanced force F is measured in newtons (N), the mass m is measured in kilograms (kg) and acceleration a is measured in metres per second per second (m/s2). Newton's Second Law of Motion is concerned with the effect that unbalanced forces have on motion. An unbalanced force acting on an object causes it to accelerate. There are two points to note about the acceleration of an object when an unbalanced force acts on it: The bigger the unbalanced force acting on the object the bigger the acceleration of the object. The more mass the object has the more inclined it is to resist any change in its motion. For example, if you apply the same unbalanced force to a mass of 1000 kg and a mass of 1 kg, the acceleration (change in motion) of the 1000 kg mass will be much less than that of the 1 ...
force is nothing but a product of mass and acceleration. for eg: assume a situation where a piece of paper flies at a speed of 50mph due to wind and hit a human body, now the human body is not injured since the mass of the paper is very very less. but when a bus traveling at the same speed hit a human body, the human body will be severely injured, this is because of the mass variance, resulting in the force variance.