What Is Force?
A force is a push or pull that changes an object's state of motion. Newton's second law ties force to mass and acceleration (F = ma), while the weight of an object near a planet's surface is the particular force produced by gravity (W = mg). Friction is a contact force that resists sliding, proportional to the normal force pressing the surfaces together (f = μN).
This calculator solves each of these three relations, so you can enter any two known quantities and recover the third, whatever the unknown happens to be.
Formula
F = m·a (Newton’s second law)
W = m·g (weight)
f = μ·N (friction force)
Units: F (N), m (kg), a (m/s²), g (m/s²), μ (dimensionless), N (N).
Applications
- Computing the net force accelerating a car or the mass needed for a target acceleration
- Finding how much weight a hoist must support
- Determining whether the friction between tyres and the road is enough to stop a vehicle
- Estimating the clamping force needed to hold a workpiece against a cutting tool
Sources
- Halliday, D., Resnick, R., & Walker, J. (2018). Fundamentals of Physics (11th ed.). Wiley.
- Young, H. D., & Freedman, R. A. (2019). University Physics with Modern Physics (15th ed.). Pearson.