- #1
rockclimber
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Homework Statement
I am trying to learn enough physics to understand forces in climbing anchors and am stuck with an exercise problem that I am unable to understand my misconception.
Mass-less rope, no friction.
diagrams
https://docs.google.com/drawings/pub?id=1ji6WWzHGx_GwYkb6vneJJCiyjGd8fUAREIR_6HLZbAE&w=960&h=720
Homework Equations
The problem question is diagram D
SB is a spring balance
T1 = 98n, correct
T3 = 98n, correct
SB = 196n, wrong, ( 98n is the correct answer )
The Attempt at a Solution
Isolating each side as in diagram B
T1 = 98n = TB1 = TB2
TB1 force is to the left, TB2 force is to the left so they will not be added together
( from a experimental view I could hold the force exerted 98n )
Putting them back together again as in diagram C
T1 = 98n = T3
TC1 = T1 = 98n
TC2 = T3 = 98n
TC1 + TC2 = 196n
TC1 force is to the left, TC2 force is to the right, so they add together
( from a experimental view I would not attempt the experiment, could be painful )
The tension force in the rope has to be equal in Diagram A
T1 = T2 = T3
but T1 and T3 are downward forces that have to be transmitted somewhere and the only place is T2 so what is T2 ?
T2 = T1 + T3 = 2x98n = 196n
as T1 = T2 = T3 , ( T1 = 98n, T2 = 98n, T3 = 196n, therefore the tension will balance to 392n / 3 = 130n )
Hopefully you can see I have tried to understand but have come to the conclusion that I have a fundamental misconception as regards tension force, could it be something similar to the common mass and weight misconception. ?