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Home/Classical Mechanics/Force Diagram Builder

Force Diagram Builder

Place objects, add force vectors, see net force and resulting acceleration.

Object

2 kg

Force 1

12 N
0 °

Force 2

8 N
90 °

Force 3

6 N
180 °

Force 4

10 N
-90 °

Measured values

ΣF_x12.00N
ΣF_y8.00N
|ΣF|14.42N
a_x = ΣF_x / m6.000m/s²
a_y = ΣF_y / m4.000m/s²
|a|7.211m/s²

About this model

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.