Skip to content
StickMan Physics

StickMan Physics

Animated Physics Lessons

Menu
  • Home
    • Stickman Physics Music: Blending Science with Sound
    • Unit 1: One Dimensional Motion: Physics Introduction
    • Unit 2: Two Dimensional Motion: Projectile and Non-Projectile
    • Unit 3: Newton’s Laws of Motion and Force
    • Unit 4: Universal Gravitation and Circular Motion
    • Unit 5: Work, Power, Mechanical Energy, and Simple Machines
    • Unit 6: Momentum Impulse and Conservation of Momentum
    • Unit 7: Electrostatics
    • Unit 8: Current and Circuits
    • Unit 9: Magnets and Magnetism
    • Unit 10: Waves
    • Unit 11: Electromagnetic Waves
    • Unit 12: Nuclear Physics
  • Table of Contents
  • Practice
  • Equation Sheet
  • Digital Learning
  • Contact
Menu

Tension: Force That Results From Stretching

Tension Force

Tension or tensile force in a rope or stand that results from that object being stretched. See how to approach a variety of tension problems here.

Tension (FT) is the pulling force exerted by a strand (ie. string) in the opposite direction of a force applied. (Unit: N)

 

Tension

When tension up is equal to weight down

There is no net force and therefore no acceleration.  The state of motion remains.  Inertia would keep a moving object moving and an object at rest would remain at rest.

  • Static Equilibrium: When tension up is equal to weight down but the object is at rest (no motion)
  • Dynamic Equilibrium: When tension up is equal to weight down an object moves with constant velocity
when tension up equals force down

When tension up is greater than weight down

  • Net force (Fnet) would be up
  • An object would accelerate up
  • The amount of acceleration would depend on mass (m) following Newton's Second Law (Fnet = ma)
when tension is greater than weight

When tension up is less than weight down

  • Net force (Fnet) would be down
  • An object would accelerate down
  • The amount of acceleration would depend on mass (m) following Newton's Second Law (Fnet = ma)
Tension up less than weight down

When tension up is less than weight down but on a horizontal surface

  • If the object comes to rest on a horizontal surface, normal force would make up the difference putting the system in equilibrium
  • FT + FN = -FW
  • Tension and normal force up would equal the magnitude of weight down.  The negative in the equation representing the opposite direction
Tension and normal force

Example Problems

Q1: What is the tension in the rope necessary to lift a 150 N object at a constant velocity up?

Answer: 150 N

Because constant motion means there is no acceleration so net force equals zero.  In order to have no net force the force of tension up must equal the weight down.

No Net Force Question

Q2: What is the normal force of a 15 kg object when on the ground and a rope with 50N of tension is pulling up?

Because the object is at rest the net force is zero.  The weight down is:

Fw = mg

Fw = (15)(10) = 150 N down

The force up must be equal since the object is at rest.

Sum of forces = 0 so force up must equal force down

Normal Force Up + Tension Up = Weight Down

FN + FT = Fw

FN + 50 = 150

FN = 100 – 50 = 100 N Up

Answer: 100 N Up  

 

tension and normal force problem

Tension with Multiple Vertical Ropes

When there is one rope up all of the weight is supported by that one rope and the tension is equal to weight.

When there are multiple ropes all directed straight up each will support an equal amount of weight.  To find this you would divide the weight by number of strands.

 

Q3: Susie, who weighs 650 N, suspends herself from the monkey bars holding herself up with both hands horizontal.  What is the tension in each arm?

650 N total weight and two arms and the force is up opposing the weight down.

650/2 = 325 N up

Answer: 325 N Up

 

Tension With Multiple Ropes

Divide by the number of ropes for tension in each when you have multiple ropes suspending an object vertically.

Tension at Equal Angles From the Vertical

As the angle from the vertical increases tension increases.  Tension is the most when the painting is at the highest point in the animation and the angle (Ө) is the most.

The greater the angle the more the tension

Calculating Tension When at Equal Angles From the Vertical

How to solve tension at an angle when at equal angles.

A. Figure what each rope has to lift vertically

B. Solve for the hypotenuse for the tension this individual rope

Tension At Angle Steps

Q4: What is the tension in each of two ropes holding up a 9 kg mass at 35° from the vertical as seen to the right

Start by finding the weight which would be supported by the ropes:

FW = mg

FW = (9)(10) = 90

Figure out what each of the ropes would have to support:

Each of the 2 ropes tension would be 90/2 = 45 N if directed straight up since they support the weight equally.

Figure out that the tension actually is:

Set a right triangle up with 45 N as the vertical and solve for the hypotenuse:

tension problem

Cos Ө = Adj/Hyp

Hyp = Adj/(Cos Ө)

Hyp = (45)/(Cos 35)= 54.9 N

The tension in each rope would be 54.9 N

Angle Tension Example
626

Tension Quiz

1 / 5

How much tension must be in a rope attached above an object if the normal force on a 500 N object is 100 N.

tension

2 / 5

Tension in rope at angle

Solve for the tension in one of the ropes suspending the object above.

tension at equal angles

3 / 5

What is the tension in each of two ropes vertically suspending a 45 kg object? (use g = 9.8 m/s/s)

Tension if a single rope would have the equal magnitude to the weight down.  With two ropes both directed up, they are sharing the weight so divide by two.

Fw = mg

Fw = (45)(9.8) = 441 N

441/2 = 220.5 N

4 / 5

What is the tension in a rope suspending a 45 kg object? (use g = 9.8 m/s/s)

Tension up would have the equal magnitude to the weight down

Fw = mg

Fw = (45)(9.8) = 441 N

5 / 5

What is the tension in a rope when you apply a force of 100 N to pull an object forward in constant motion.

rope tension

Your score is

LinkedIn Facebook Twitter
0%

  • Continue to Forces on an Incline Plane
  • Back to the Main Forces Page
  • Back to the Stickman Physics Home Page
  • Equation Sheet

StickMan Physics Logo  StickMan Physics Home

Stickman Physics Music Page

Unit 1: One Dimensional Motion
Unit 2: 2D Motion
Unit 3: Newton’s Laws and Force
Unit 4: Universal Gravitation and Circular Motion
Unit 5: Work, Power, Mechanical Advantage, and Simple Machines
Unit 6: Momentum, Impulse, and Conservation of Momentum
Unit 7: Electrostatics
Unit 8: Current and Circuits
Unit 9: Magnetism and Electromagnetism
Unit 10: Intro to Waves
Unit 11: Electromagnetic Waves
Unit 12: Nuclear Physics

AP Physics 1 Pages (Deeper Dive into Concepts)

DIY Creations for Fun and Physics

Teachers: Do you want lessons and handouts already put together?  Find resources at TeachersPayTeachers.

©2025 StickMan Physics | Built using WordPress and Responsive Blogily theme by Superb

Terms and Conditions - Privacy Policy