Mechanics
Newton's Second Law
The net force equals mass times acceleration. Newton's fundamental law.
Variables
FN
Net force
Sum of all forces
In SI units: kg·m/s²
mkg
Mass
Inertial mass
Allowed values: 0 or more
am/s²
Acceleration
Resulting acceleration
Derivation
Fundamental principle. More generally: F = dp/dt.
Your notes
0/5000
Check value
Round inputs run through this page's calculator. Use it to test your own working or a rearranged form. It is a test case, not a real-world example.
- m = 2 kg (Mass)
- a = 3 m/s² (Acceleration)
Result: F = 6 N
Other mechanics formulas with the same quantities
- Terminal Velocity (Dynamics) shares Mass
- Acceleration (Kinematics) shares Acceleration
- Kinematic Equation 1 (Kinematics) shares Acceleration
- Kinematic Equation 2 (Kinematics) shares Acceleration
- Kinematic Equation 3 (Kinematics) shares Acceleration
Where this formula is listed
- Mechanics formulas, under Dynamics, alongside Friction Force, Hooke's Law, Drag Force, Center of Mass (Two Objects) and Pressure.
- In the mechanics list it comes after Average Velocity and before Weight.
- Mechanics formula sheet, one of 58 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Newton's Second Law formula?
Newton's Second Law is written F = ma. The net force equals mass times acceleration. Newton's fundamental law. It belongs to Mechanics, under Dynamics.
What are the units in F = ma?
In SI units, F is net force, measured in kg·m/s²; m is mass, measured in kg; a is acceleration, measured in m/s².
How is the Newton's Second Law formula derived?
Fundamental principle. More generally: F = dp/dt. The result is F = ma.