Draw objects and add force vectors (gravity, normal, tension, friction). Resolve components and check equilibrium conditions.
The guide
You build a diagram by placing an object, then attaching force vectors - weight, normal, tension, friction, or a custom force - each with magnitude and direction. The tool resolves every vector into x and y components, sums them, and reports the net force and whether the object is in equilibrium. The thing most users get wrong first: the normal force is perpendicular to the contact surface, not vertical, while weight always points straight down. On an incline those two directions never coincide, so drawing either one wrong invalidates the whole check.
A concrete input and expected output from the current implementation.
Input
10 kg block on a 30° incline, coefficient of friction 0.2, g = 9.81 m/s². Add weight, normal, and friction; check equilibrium.
Expected output
Weight: 98.1 N straight down. Normal force: 84.96 N perpendicular to the incline. Weight component down the slope: 49.05 N. Maximum static friction: 0.2 × 84.96 = 16.99 N up the slope. The demand exceeds the cap, so the block slides: net force 32.06 N down the slope, acceleration 3.21 m/s². Equilibrium: no.
The weight splits into 98.1 sin 30° = 49.05 N along the slope and 98.1 cos 30° = 84.96 N into the slope, which the surface balances with the normal force. Friction can supply at most 0.2 × 84.96 = 16.99 N, below the 49.05 N demand, so the forces cannot balance and the block accelerates down the slope.
Each force is decomposed onto perpendicular axes, usually horizontal and vertical or parallel and perpendicular to the surface, using magnitude times cos(angle) and magnitude times sin(angle). The tool sums all x components and all y components separately; the two totals form the net force. Equilibrium requires both totals to be zero, within a small rounding tolerance.
Friction is a reaction, not a fixed input: it opposes relative motion and its maximum static value is the friction coefficient times the normal force. The tool caps friction at that product and compares it with the force demand along the surface. If the demand exceeds the cap, the diagram cannot balance and the surplus shows up as a net accelerating force.
Check the directions first: the normal force must be perpendicular to the ramp, and weight must point straight down, not perpendicular to the ramp. Then check friction, which can supply at most the coefficient times the normal force. If the force down the ramp exceeds that cap, the object genuinely slides, and 'not in equilibrium' is the correct answer.
No, the check is a static analysis: it asks whether the drawn forces could balance with friction at its maximum static value. An object that balances on paper can still be accelerating in reality, for example when kinetic friction applies, which is usually smaller than the static cap. Use the tool for statics problems, and treat a 'balanced' result on a moving object with suspicion.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
Sent. Thank you.
