Newton's second law of motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. In equation form, this is expressed as:

F⃗net=ma⃗\vec{F}_{net}=m\vec{a}Fnet​=ma

where F⃗net\vec{F}_{net}Fnet​ is the net force applied to the object, mmm is the mass of the object, and a⃗\vec{a}a is the acceleration produced

. More fundamentally, Newton originally described this law in terms of momentum (p⃗=mv⃗\vec{p}=m\vec{v}p​=mv), stating that the rate of change of momentum of an object is equal to the net force acting on it:

F⃗net=dp⃗dt\vec{F}_{net}=\frac{d\vec{p}}{dt}Fnet​=dtdp​​

For objects with constant mass, this reduces to the familiar form F⃗net=ma⃗\vec{F}_{net}=m\vec{a}Fnet​=ma

. This law quantitatively describes how forces cause changes in the motion of objects, linking force, mass, and acceleration in a cause-and-effect relationship. When no net force acts on an object, it does not accelerate and remains in mechanical equilibrium