How is net force calculated?

All applied forces are added as vectors. The net force divided by the object’s mass gives acceleration; directions follow the vector sum.

Force Diagram Builder

Build free-body diagrams by placing objects and attaching force vectors. The sim combines forces into a net vector and shows the resulting acceleration direction and magnitude consistent with F = ma.

Who it's for: Students practicing Newton’s laws, force components, and net-force reasoning.

Key terms

free-body diagram
net force
Newton’s second law
vector sum
equilibrium

How it works

Add up to four forces on a single object. Each force has a magnitude (newtons) and an angle measured from the +x axis counterclockwise — 0° points right, 90° points up. Colored arrows are the forces you enable; the thick cyan arrow is the net force ΣF. The dashed magenta arrow is acceleration a = ΣF/m (same direction as ΣF; length is scaled for visibility). The diagram redraws every frame as you move the sliders.

Key equations

F_x = |F| cos θ, F_y = |F| sin θ

ΣF = Σ F_i (vector sum)

a = ΣF / m

Frequently asked questions

How is net force calculated?: All applied forces are added as vectors. The net force divided by the object’s mass gives acceleration; directions follow the vector sum.

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