Calculadora de Tensão (corda/fio)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
T = m·(g+a)
About this calculator
This tension calculator determines the tensile force in a rope or wire supporting an object vertically, considering acceleration. Tension is calculated by T = m·(g + a), where m is mass, g is gravity (≈9.8 m/s²), and a is vertical acceleration. If the object is stationary or at constant speed, a = 0, so T = m·g (weight). Useful for basic physics problems, engineering, or everyday scenarios like elevators or cranes.
How to use: enter mass in kg, vertical acceleration in m/s² (positive upward, negative downward), and local gravity (default 9.8). Result is tension in Newtons. Example: 10 kg object accelerating upward at 2 m/s² gives T = 10·(9.8+2) = 118 N. If accelerating downward, a is negative: T = 10·(9.8-2) = 78 N. Tension is highest when accelerating upward and lowest when accelerating downward.
Cautions: formula assumes ideal rope (massless, inextensible) and no friction. Real cables with elasticity or self-weight yield approximations. Ensure consistent units (kg, m/s²). Does not account for angles or pulleys; for inclined cases, use the inclined plane tension calculator.
Frequently asked questions
What does negative tension mean?
Negative tension is not physically meaningful; it indicates the rope would be slack. If the calculation gives a negative value, the object is in free fall because downward acceleration exceeds gravity.
Can I use this calculator for inclined ropes?
No, this formula is only for vertical linear motion. For inclined ropes, tension depends on the angle and other forces.
What is the difference between tension and weight?
Weight is the gravitational force (m·g). Tension is the force transmitted by the rope, which can be greater than weight if accelerating upward, or less if accelerating downward.
Does the calculator consider the rope's mass?
No, it assumes an ideal massless rope. If the rope has significant mass, tension varies along its length and the calculation is more complex.
How to convert Newtons to kgf?
Divide the value in Newtons by 9.8 to get approximately kgf (kilogram-force). Example: 98 N ≈ 10 kgf.