Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Tension is the force exerted by a string, rope, or cable when it is pulled tight by forces acting from opposite ends. It is a contact force that acts along the length of the medium and transmits force between objects.
5 Must Know Facts For Your Next Test
Tension always acts along the direction of the string or rope.
In a massless and frictionless pulley system, tension remains constant throughout the entire length of the rope.
Tension can be calculated using Newton's Second Law: sum of forces equals mass times acceleration ($\sum F = ma$).
When dealing with an object in equilibrium, tension must balance other forces such as gravity or friction.
The units of tension are Newtons (N), consistent with other forms of force.
$\sum F = ma$, which states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.