Newton's Second Law of Motion

Newton’s Second Law of Motion

The acceleration of an object is proportional to the resultant force acting on it and inversely proportional to the object’s mass.

Newton’s second law explains what happens when a non-zero resultant force acts on an object. A resultant force occurs when the forces acting on an object are not balanced. A resultant force acting on an object will cause a change in the object’s motion.

This change in motion is an acceleration:

• Speeding up
• Slowing down
• Changing direction

Newton’s second law can be expressed as an equation:

$$F = ma$$

Where:

• $F$ = resultant force on the object, measured in newtons (N)
• $m$ = mass of the object, measured in kilograms (kg)
• $a$ = acceleration of the object, measured in metres per second squared (m/s²)

The acceleration occurs in the same direction as the resultant force.