• Engineering and Architecture
  • Management and Business Administration
  • Medicine and Allied Sciences
  • Law
  • Animation and Design
  • Media, Mass Communication and Journalism
  • Finance & Accounts
  • Computer Application and IT
  • Pharmacy
  • Hospitality and Tourism
  • Competition
  • School
  • Study Abroad
  • Arts, Commerce & Sciences
  • Learn
  • Online Courses and Certifications
Tension - Definition, Examples, Units, Formula, FAQs

Tension - Definition, Examples, Units, Formula, FAQs

Edited By Team Careers360 | Updated on Jul 02, 2025 04:36 PM IST

What is Tension Force? Tension in physics is a contact force. The tightness of a rope or string when you try to stretch it is called tension.
Tension definition in physics
When two or more physical objects come into touch with each other, they exert forces on each other. These contact forces are given different names depending on the objects in touch. The force is called tension if one of the items in contact is a string, rope, cable, or spring.

Tension - Definition, Examples, Units, Formula, FAQs
Tension - Definition, Examples, Units, Formula, FAQs

Tension Physics -Examples

A stone is suspended with the help of a thread and its free end is fastened to the ceiling, as shown in Figure

Gravity pushes a stone attached to a string down all the time, but the stone does not fall since it is held by the string. As a result, there is a force that pulls the stone upward to support it against gravity.

Tension Physics Examples

(Image drawn using Microsoft paint)

The upward tension force balances the gravitational force in the case above, as seen in the diagram below.

tension force balance

(Image drawn using Microsoft word)

Also read -

Tension definition

When forces working from opposite ends pull a cable, rope, wire, or string tight, the tension force is conveyed through the cable, rope, wire, or string. It travels the length of the cable, pulling evenly on the items at both ends.

The action-reaction pair of forces acting at each end of the aforementioned elements can alternatively be defined as tension. Tension can be thought of as the polar opposite of compression.

Cables and ropes can be utilised to exert force because they can efficiently transfer force over a short distance. Because the ropes cannot effectively push, tension is the pulling force.

Tension meaning

In physics, a tension force is the force created when a rope, string, or cable is stretched under a force. Tension is applied along the length of the rope/cable in the opposite direction of the force applied.

Tension meaning in English

The state of being stretched tight.

Tension- units

For suspended objects in equilibrium, the tension is equal to the mass of the object times its gravitational acceleration.

Tension SI units are N (newtons), or kg-m/s²

Tension formula

The tension in the cable/string, which pulling up object, is equal to weight force, i.e. mg, where m is a mass as well as g is acceleration induced by gravity, which is dragging down the object, the system has a constant velocity and is in equilibrium

T=mg (mass multiplied by gravitation)

T is for tension, m is for mass, kg is for gravitational force, and g is for gravitational force.

Related Topics Link,

Direction of tension force

This "pull" is a force we refer to as tension. As a result, tension will point away from the mass and toward the string. The string, in the instance of the hanging mass, pulls it up, exerting an upward force on mass, along with tension upwards..

Newton's Laws and Tension Force:

The tension is the final application of Newton's law. Tension normally arises when a force is transmitted through cables or rope. Consider a block that is being dragged by a rope. The person pulling on one end of the rope isn't in contact with the block at the other end, so he or she can't exert direct force on it. As a result, the force is applied to the rope, which then transmits it to the block. The tension force is the force that the block feels as it pulls on the rope.

Classical mechanics is concerned with massless ropes and cables. If a cable or rope has no mass, it transmits force perfectly from one end to the other. For example, if a man pulls the massless rope with 30 N of power, the block will only be subjected to 30 N of force.

The overall force on the rope must be zero at all times, which is a key characteristic of the massless rope. Newton's second law can be used to demonstrate this. If a net force is applied to a massless rope, the result is infinite acceleration A=F/m and the rope's mass is zero.

Because the situation described above is physically impossible, the massless rope will never experience net force.

Also Read:

Why is the Tension of a Massless String Constant?

Because a string is extended and non-rigid, tension exists throughout the thread rather than being applied at a single location, the concept of tension in a string might be difficult to grasp.

What is the Importance of Tension Force?

All physical things that come into contact with one another can exert forces on one another. It's vital to remember that tension is a pulling force because ropes can't effectively push. When you try to pull anything with a rope, it becomes slack and loses the tension that allowed it to pull in the first place.

Also check-

NCERT Physics Notes:

Frequently Asked Questions (FAQs)

1. How can we determine the tension force's direction?

The pull, which is called tension, is the direction of tension. A thread pulls the mass upwards in the case of a hanging mass, hence the string/rope exerts an upper force on the mass and the tension is on the upper side.

2. When two equal 5 N forces are applied to the spring's one end and if the other end is hung on a wall, what is the tension experienced by the spring?

The string has a tensile force of 10 N. 

3. What effect does gravity have on the tension force?

The gravitational force acts in the opposite direction of tension. If an object is suspended, tension must be used to keep it balanced; otherwise, gravity will cause it to fall.

4. In what situations would the tension force between two bodies tied by a single rope differ?

Because the rope works as a force transfer agent, there should never be a situation when two items connected by one rope are subjected to tension forces of different magnitudes.

5. Why does tension always produce zero work?

The amount of work done is determined by both force and displacement. Although tension is a force, it does not result in any displacement. In the case of tension, W = F 0 = 0 if the work done is given by the equation W = FS where F is the force and S is the displacement. As a result, tension produces little work.

6. What is tension in physics?
Tension is the force exerted by a rope, string, or cable when it is pulled tight. It acts along the length of the object and is always directed away from the point of application. Tension is a contact force that occurs when an object is stretched or pulled.
7. How does tension differ from other forces like gravity or friction?
Unlike gravity, which is a long-range force acting on all objects with mass, tension is a contact force that only exists when objects are connected by a rope or string. Friction opposes motion between surfaces, while tension can either oppose or assist motion, depending on the situation.
8. Can tension ever be zero in a rope?
Yes, tension can be zero in a rope when it's slack or not supporting any load. For example, a loose clothesline or a string hanging freely has zero tension.
9. Why is tension always the same throughout an ideal string?
In an ideal string (massless and inextensible), tension is constant throughout because the string cannot store or dissipate energy. Any change in tension would cause acceleration of part of the string, violating the assumption of an ideal string.
10. How does the mass of a rope affect tension?
In real ropes with mass, tension varies along the length due to the rope's weight. The tension is highest at the top where it supports the entire rope's weight and decreases towards the bottom.
11. What are the units of tension?
Tension, being a force, is measured in Newtons (N) in the SI system. Other units include dynes in the CGS system or pounds-force in the imperial system.
12. How is tension related to Newton's Third Law?
Tension exemplifies Newton's Third Law: when an object pulls on a rope, the rope pulls back with an equal and opposite force. This is why tension acts in both directions along a rope.
13. Can tension be greater than the weight it's supporting?
Yes, tension can exceed the weight it's supporting. For instance, when you quickly lift a heavy object with a rope, the tension momentarily exceeds the object's weight due to the additional force needed for acceleration.
14. What's the difference between tension and stress?
While both relate to forces in materials, tension specifically refers to the pulling force in a rope or string. Stress is a more general term describing force per unit area within a material, which can be tensile, compressive, or shear.
15. How does the angle of a rope affect the tension in it?
The angle of a rope influences tension significantly. As the angle between two sections of rope increases, the tension required to support a given weight also increases. This is why tightrope walkers use very taut ropes.
16. What is the formula for tension in a vertical rope supporting a mass?
For a mass m hanging from a vertical rope in equilibrium, the tension T equals the weight of the mass: T = mg, where g is the acceleration due to gravity (approximately 9.8 m/s² on Earth).
17. How does acceleration affect tension in a rope?
Acceleration changes tension. If an object suspended by a rope accelerates upward, the tension increases above the object's weight. If it accelerates downward, the tension decreases below the object's weight.
18. What happens to tension when a rope breaks?
When a rope breaks, the tension in that rope instantly becomes zero. The load previously supported by the tension is then transferred to other supporting structures or falls if unsupported.
19. Can tension be negative?
In physics calculations, tension is typically considered positive when pulling and zero when slack. Negative tension isn't physically meaningful for ropes or strings, as they can't push (compress).
20. How is tension different in static vs. dynamic situations?
In static situations, tension balances other forces to maintain equilibrium. In dynamic situations, tension can vary with acceleration, contributing to changes in motion of connected objects.
21. What's the relationship between tension and elasticity?
While ideal strings are considered inelastic, real materials stretch under tension. The relationship between tension and stretch is described by Hooke's Law for elastic materials, where tension is proportional to the extension.
22. How does friction affect tension in a pulley system?
Friction in pulleys causes tension to vary on either side of the pulley. The tension on the side moving against friction is higher than the side moving with friction, unlike in an ideal, frictionless pulley where tensions are equal.
23. What's the difference between tension and normal force?
Tension acts along the length of a string or rope, while normal force acts perpendicular to a surface. Both are contact forces, but they occur in different contexts and directions.
24. How do you calculate tension in a string supporting two masses?
For a string supporting two masses m1 and m2, the tension T equals the total weight: T = (m1 + m2)g, where g is the acceleration due to gravity. This assumes the string is ideal and the system is in equilibrium.
25. Can tension cause a string to break?
Yes, if the tension exceeds the string's breaking strength (maximum tension it can withstand), the string will break. Every material has a specific breaking strength determined by its composition and thickness.
26. How does tension relate to centripetal force in circular motion?
In circular motion, tension can provide the centripetal force necessary to maintain the circular path. For example, when swinging an object in a circle, the tension in the string provides the centripetal force.
27. What's the tension in a massless string looped over a frictionless pulley with equal masses on both ends?
In this ideal case, the tension throughout the string is equal to the weight of one mass: T = mg, where m is the mass of one object and g is the acceleration due to gravity. The system remains in equilibrium.
28. How does the concept of tension apply to molecules and atomic bonds?
At the molecular level, tension manifests as the stretching of chemical bonds. The force required to break these bonds is analogous to the breaking strength of a macroscopic string or rope.
29. What's the difference between tension and compression?
Tension involves stretching or pulling forces, while compression involves squeezing or pushing forces. Ropes and strings typically experience tension, while pillars or springs can experience both tension and compression.
30. How does tension affect the speed of waves on a string?
The speed of waves on a string increases with higher tension. The wave speed is proportional to the square root of the tension divided by the linear density of the string.
31. Can tension exist in fluids?
While fluids don't support tension in the same way solids do, surface tension in liquids is a related concept. It results from cohesive forces between liquid molecules at the surface.
32. How does tension relate to work and energy?
When an object moves along the direction of tension, work is done. The work done by tension equals the product of tension force and displacement in the direction of the force, contributing to changes in the object's energy.
33. What's the tension in a rope used to tow a car?
The tension in a tow rope depends on several factors: the car's mass, the acceleration of the system, friction with the road, and any incline. It's generally greater than the force needed to overcome the car's rolling resistance.
34. How does tension vary in a hanging chain?
In a hanging chain, tension varies with position. It's maximum at the top where it supports the entire chain's weight and minimum (theoretically zero) at the bottom. This variation creates the characteristic catenary curve.
35. What's the relationship between tension and potential energy in a stretched elastic string?
In an elastic string, stretching increases both tension and elastic potential energy. The potential energy stored is proportional to the square of the extension, as described by the elastic potential energy formula: PE = ½kx², where k is the string's spring constant and x is the extension.
36. How does air resistance affect tension in a falling parachute?
As a parachute opens, air resistance increases, reducing the acceleration of the fall. This causes the tension in the parachute strings to increase, eventually reaching a value that balances the weight of the parachutist and creates a constant terminal velocity.
37. What's the tension in a string holding a pendulum at its maximum displacement?
At the maximum displacement of a simple pendulum, the tension in the string is greater than the weight of the bob. It's the vector sum of the weight and the centripetal force needed to keep the bob moving in an arc.
38. How does tension relate to stress-strain curves in materials science?
Tension is closely related to the stress in a stress-strain curve. As tension (force) increases, stress (force per unit area) in the material increases. The strain represents how much the material stretches in response to this stress.
39. Can tension ever change instantaneously?
In idealized physics problems, tension can change instantaneously, such as when a mass is suddenly attached to a hanging string. In reality, there's always a brief period of adjustment as stress waves propagate through the material.
40. How does tension in muscles relate to physics concepts of tension?
Muscle tension is analogous to tension in ropes. When a muscle contracts, it creates a pulling force (tension) on the bones it's attached to. This biological tension follows the same physical principles as tension in inanimate objects.
41. What's the tension in a rotating string with an attached mass (like a conical pendulum)?
In a conical pendulum, the tension in the string provides both the centripetal force for circular motion and supports the weight of the mass. It's greater than the weight of the mass and increases with angular velocity.
42. How does tension affect the resonant frequency of a string instrument?
Increasing the tension in a string instrument (like tightening a guitar string) increases its resonant frequency. This is why tightening a string produces a higher pitch. The frequency is proportional to the square root of the tension.
43. What's the difference between tension and torque?
While both are forces, tension acts along the length of an object, while torque is a rotational force that causes twisting or turning. Tension can create torque if applied at a distance from an axis of rotation.
44. How does tension relate to Young's modulus?
Young's modulus describes a material's resistance to deformation under tension. It's the ratio of tensile stress (related to tension force) to tensile strain (the proportional deformation). Materials with higher Young's modulus require more tension to stretch by the same amount.
45. Can tension ever be perpendicular to the length of a string?
Tension, by definition, acts along the length of a string or rope. Forces perpendicular to the string's length are not tension but could be other types of forces like normal force or friction.
46. How does tension in a string affect its natural frequency of vibration?
Increasing tension in a string increases its natural frequency of vibration. The frequency is proportional to the square root of tension divided by the linear density of the string. This principle is used in tuning string instruments.
47. What's the tension in a rope bridge, and how does it change when someone walks on it?
The tension in a rope bridge is complex and varies along its length. It's highest at the support points and changes dynamically as weight is added. When someone walks on the bridge, the tension increases and redistributes, with local increases where the person stands.
48. How does tension relate to the concept of mechanical advantage in pulley systems?
In pulley systems, tension is distributed among multiple rope segments, reducing the force needed to lift a load. This creates a mechanical advantage. The more rope segments supporting the weight, the lower the tension in each segment, making it easier to lift heavy loads.
49. What's the difference between tension and pressure?
Tension is a pulling force along the length of an object, while pressure is force per unit area acting on a surface. Tension is typically associated with strings or ropes, while pressure is more commonly discussed with fluids or gases.
50. How does temperature affect tension in materials?
Temperature changes can significantly affect tension in materials. Most materials expand when heated and contract when cooled. In constrained systems, this can lead to increased tension with cooling (like tightening guitar strings) or decreased tension with heating.
51. What's the role of tension in the formation of soap bubbles?
Surface tension, a related concept to tension in strings, is crucial in soap bubble formation. It's the force that allows the bubble to maintain its spherical shape by minimizing surface area. The tension in the soap film balances the pressure difference between the inside and outside of the bubble.
52. How does tension affect the speed of sound in a string?
The speed of sound in a string increases with tension. The relationship is similar to that for wave speed: the speed of sound is proportional to the square root of the tension divided by the linear density of the string.
53. What's the tension in a rotating object, like the spokes of a bicycle wheel?
In a rotating object like a bicycle wheel, the spokes experience tension that increases with rotational speed. This tension provides the centripetal force necessary to keep the rim circular and supports the weight of the bicycle and rider.
54. How does the concept of tension apply in relativity and spacetime?
While classical tension applies to physical objects, in relativity, the concept extends to spacetime itself. Gravitational waves, for instance, can be thought of as "ripples" in the fabric of spacetime, analogous to waves on a stretched membrane under tension.
55. What's the relationship between tension and the catenary curve formed by a hanging chain?
The catenary curve is the shape formed by a chain or rope hanging under its own weight. The tension at any point in the chain is tangent to the curve at that point. The shape is determined by the balance between the tension in the chain and the gravitational force acting on each segment.

Also Read

Skidding Of Object On A Rotating Platform

02 Jul'25 07:45 PM

Skidding Of Vehicle On A Level Road

02 Jul'25 07:42 PM

Sticking Of A Block With Accelerated Cart

02 Jul'25 07:42 PM

Centripetal Force For Non-uniform Circular Motion

02 Jul'25 07:41 PM

Reaction Of Road On Car

02 Jul'25 07:41 PM

Angle of Repose

02 Jul'25 07:40 PM

Graph Between Applied Force And The Force Of Friction

02 Jul'25 07:40 PM

Types Of Collision

02 Jul'25 07:33 PM

Recoiling Of Gun

02 Jul'25 07:33 PM

Motion Of Connected Blocks Over Pulley

02 Jul'25 07:33 PM

Articles

Questions related to

Have a question related to ?
Respected sir, I request you to extend the time for registration of UG NEET exam application. Due to exam tension I could not notice the deadline for application. And the family condition is like they cannot go with long term even I have been taking the coaching class. Please extend the time sir.

Hello Paramesha,

The deadline extension for NEET UG is in complete discretion of competitive authority i.e. National Testing Agency. If you have valid genuine reason you may raise. You may raise your concern on below NTA website by contacting on number or dropping them a email.

https://www.nta.ac.in/contactus

Hope this will solve your concern. All the best !!


Read Complete Answer
Aparna Patil 26 March,2025

Question : Cold war refers to

Option 1: Tension between East and West

Option 2: Ideological rivalry between the Capitalist and Communist world

Option 3: Tension between superpowers

Option 4: All of the above

Correct Answer: All of the above


Solution : The correct option is All of the above.

The phrase "Cold War" refers to the geopolitical tension and competition that prevailed in the wake of World War II, particularly between the United States and its Western allies (commonly referred to as the "West") and the Soviet Union and its allies (often referred to as the "East"). While there was political, military and economic competition, there was never an actual armed confrontation between the great nations.

Read Complete Answer
Team Careers360 24 January,2024

Question : An oil drop spreads over water because:

Option 1: oil is lighter than water.

Option 2: oil is more viscous.

Option 3: oil does not mix with water.

Option 4: surface tension of oils is much smaller than that of water.

Correct Answer: surface tension of oils is much smaller than that of water.


Solution : The correct option is surface tension of oil is less than that of water.

The surface tension of water causes oil droplets to disperse over it. Water has a higher surface tension than oil, therefore when oil is spilt over it, the water's higher surface tension pushes the oil in all directions, causing it to spread throughout the water. But oil only spreads when it comes into touch with the water's surface at a specific angle. As droplet size and interfacial tension increase, so does the maximum spreading length of oil droplets.

Read Complete Answer
Team Careers360 16 January,2024

Question : Which of the following statements is not correct about surface tension?

Option 1: Surface tension is typically measured in dynes cm.

Option 2: The shape of the water drop is spherical due to surface tension.

Option 3: At room temperature, the surface tension of water is less than ethyl alcohol.

Option 4: The cohesive forces between liquid molecules are responsible for the phenomenon known as surface tension.

Correct Answer: At room temperature, the surface tension of water is less than ethyl alcohol.


Solution : The correct option is At room temperature the surface tension of water is less than ethyl alcohol.

Water has a greater surface tension than ethyl alcohol at a normal temperature. At room temperature, the surface tension of water is around 72 mN/m, whereas that of ethyl alcohol is roughly 22 mN/m. The higher degree of hydrogen bonding between water molecules in the bulk liquid is the cause of this discrepancy.

Read Complete Answer
Team Careers360 19 January,2024

Question : The surface tension of water on adding detergent to it:

Option 1: increases

Option 2: decreases

Option 3: no change

Option 4: becomes zero

Correct Answer: decreases


Solution : The correct option is decreases.

 

When detergent is added to water, it reduces the surface tension of the water. Surface tension is the property of a liquid that allows it to resist an external force due to the cohesive nature of its molecules. In the case of water, this is due to the hydrogen bonding between water molecules.

Read Complete Answer
Team Careers360 23 January,2024
View All
Back to top