ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: rife168 on February 04, 2012, 01:03:58 pm
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Would someone be able to explain the tension force in connected body problems and how to calculate it?
I know that there is a simple formula for it but I need an intuitive way to think about the problem before blindly plugging in values.
Thanks.
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Tension is usually the force responsible for pulling the body forward. So to calculate it you re-arrange the formula of Fnet = forces one way - forces the other way (where tension, will be one of the forces)
So in some cases you might have:
Fnet = T - Fr
As the force of T is forwards and the frictional force (Fr) is backward.
In a case, where, say a ball is being held by a wire from the roof then:
Fnet = Fg - T
As the force of T is upwards and the gravitational force (Fg) is downwards.
In a case where you are given the acceleration of the body and it's mass, then:
T = ma (where m = the total mass that that the wire is pulling)
There are various types of questions involving tension so if you provide a more narrow range of questions I'll be able to offer more help.
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How about questions with 2 masses connected by some sort of rope/wire that passes over a pulley, where both bodies are free to move vertically?
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(http://www.sewanee.edu/physics/PHYSICS101/image271.gif)
Let's say, in this case, m1 > m2
Therefore m1g > m2g and for this reason m1 will accelerate down and m2 will accelerate up
So on the left:
Fnet = Fg - T = m1a
or Fnet = m1g - T = m1a
on the right:
Fnet = T - Fg = m2a
or Fnet = T - m2g = m2a
edit: I can also give explanation of finding a for the above if needed
edit2: I've found this which might offer better explanations and working out than I can offer.
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Thanks! That helps a lot. I just needed to clear up that the forces m1g>T>m2g