Tension force

A force is a pull or push on an object caused by the interaction of the object with another object. Every time two objects interact; a force is exerted on each of them. The objects no longer feel the force when the interaction ends. A force is a quantity that is measured in terms of vectors. A vector quantity is one which has both magnitude and the direction.

Tension force

In physics, a tension force is the force developed when a rope, chain, or cable is stretched under a force. Tension is applied along the size of the rope/cable in the opposite direction of the force applied. Tension is also known by the terms stress, tensity, and tautness.

A tension force is classified as a contact force because it can only be applied when a cable and an object of interest are in contact. This force is always pulling but never pushing. Pulling less reduces tension, while pulling more increases tension.

Tension force on a string formula

A force along the size of a medium, particularly a force carried by a flexible form of media like a rope or cable, is known as tension. “Tension” is derived from the Latin word Tendons that means “to stretch.” Tendons are the flexible cords that hold muscle forces to the other parts of the body, which is no coincidence. A flexible connector, such as a string, rope, chain, wire, or cable, can only exert pulls parallel to its span; thus, a force carried by a flexible connector is tension in the same direction as the connector.

Consider the figure of a guy carrying a mass on a rope.

Newton’s second law states that the tension in the rope should equivalent to the weight of the supported mass. If the 5.00-kg mass in the illustration is stationary, its acceleration is nil, and Fnet=0. The weight w of the mass and the tension T provided by the rope are the only external forces acting on it. Thus,

Fnet=T-w=0

T and w are the tension and weight magnitudes, respectively, and their signs show direction, with +y axis being positive in this case. As a result, the tension in the rope equals the weight of the supported mass, as expected: T=w=mg

We can see that (ignoring the mass of the rope) for a 5.00-kg mass, the tension will be:

T=mg=5×9.8=49.0 N

Working with tension force

Equation for tension in a string or rope attached to a mass in different scenarios.

Where W denotes the body’s weight and m denotes the body’s mass.

• When the body is rising upwards at a constant a, the tension is T = W + ma.

• When body is moving downwards at an acceleration of a, the tension is T = W – ma.

•  The tension is T = W if the body is just suspended (not moving).

•  If the body rises at a constant rate, tension is created; T = W

Let us assume a lift accelerating upwards with an acceleration of 5 m/s2. In the lift there are 3 persons with an average mass of 70kg. We need to calculate the tension on the cable with which the lift cabin is being pulled upwards.

The total mass of the persons will be: m=3×70=210kg

The weight of the persons will be: W=210×9.8=2058 N

Now, the tension in the cable will be:

T=2058+(210×5)

    =3108 N

Therefore, the tension in the cable would be 3108N.

If we consider the lift accelerating downwards the tension in the cable will be:

T=W-ma

🡺T=2058-1050

         =1008N

Therefore, the tension in the cable will be 1008N.

Conclusion

It’s important to remember that tension is indeed a pulling force because ropes cannot effectively push. When you try to pull something with a rope, it becomes slack and loses the tension that permitted it to pull in the first place. Because they can efficiently transfer a force over a long distance, ropes and cables are helpful for exerting forces (e.g., the length of the rope). For example, a sled can be pulled by a squad of Siberian Huskies with cords attached, allowing the dogs to run with a greater range of motion than if the Huskies were required to push on the sled’s back surface from behind using normal force.