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### Course: Mechanics (Essentials) - Class 11th>Unit 6

Lesson 7: When is a lift cable most likely to break - while going up or down?

# The force of tension

Tension refers to the force that is transmitted through a string, rope, wire, or other similar object when it is pulled tight, trying to restore the object to its original, unstretched length. Learn how to solve for the strength of a tension force by using Newton’s Second Law of Motion. Created by David SantoPietro.

## Want to join the conversation?

• Why did not we consider the vertical component of T3?
• Because the vertical component of T3 doesn't affect the horizontal acceleration, which is what we were trying to find in this video.
• Is there ever a good reason to make the leftward direction positive?
• No, not really. It is considered to be "convention". It is basically something which people universally agree. For example, if your name is Dan, is there any reason for your name to be Dan? No, its a convention and that's how everyone knows you. If you changed your name to Rick, would anything about your looks be different? Nope, its just convention; you can do whatever you want but it's better to work with universally accepted stuff and as a wise man has said -
"perfectly balanced, as all things should be."
• Is there a delay from a pulling of a rope and the box moving?in other words how long does it take for those fibers to transfer the force across?
Approx
Thank You
• strictly speaking, the force travels at the speed of sound through the material
• what is tension in simple language?
• the force in an object (eg string or chain) that tries to 'stretch' the object.

eg if you pull your shoe lace, it will become straight. it has the force of tension in it
• When and why is tension different in the same string at two different points?
• As explained in the video, when the rope has mass, then one section of the rope will be pulling more mass (it will be pulling some rope and also the object) than the section farther from the object. So, close to the object, the rope pulls and exerts force on only the object and a small amount of rope. At the end of the rope (the furthest point from the object) the rope is exerting force on both the mass of the object and all of the rope between the object and the end of the rope.
• the force of tension acts on the box or on the rope?
• Tension force acts on an object through rope like things.
• If there's a system wherein we have 2 masses connected by a thread (M and m) and there's one force pulling at one end (F1 at M) and another pulling at the other free end (F2 at m) and say F1>F2.
And we are required to calculate the force of tension between the two. Will the tension be (m)(F1-F2/M+m)? I am quite confused on this one as in one such problem the answer given was something else. The tension was given as T=F2+ma.
Why is it so?
• As stated in the video the horizontal component of t3 is taken for the tension of t1 and if you want to take the tension of t3 which is at angle what would be the components of t1 and t2?