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    From WJEC Specimen paper. "One end A of a light inextensible rope AB, of length 08 m, is attached to the top of a fixed vertical pole. [...] What assumption does the word 'light' enable you to make in your solution." I put that 'light' means we can say the string has no mass, so we do not have to take into account the weight of the rope etc.

    The mark scheme, however, says that this means tension is constant throughout the rope. Is this an error with the mark scheme? If not, can someone explain why 'light' means that tension is constant? Thanks!
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    (Original post by osamabinfishing)
    From WJEC Specimen paper. "One end A of a light inextensible rope AB, of length 08 m, is attached to the top of a fixed vertical pole. [...] What assumption does the word 'light' enable you to make in your solution." I put that 'light' means we can say the string has no mass, so we do not have to take into account the weight of the rope etc.

    The mark scheme, however, says that this means tension is constant throughout the rope. Is this an error with the mark scheme? If not, can someone explain why 'light' means that tension is constant? Thanks!
    What you have said is correct, but the mark scheme has taken this one step further. Consider a rope that is not light and is being used to suspend a mass. The top of the rope will then be supporting the mass of the rope plus the suspended mass while the bottom of the rope will be supporting only the suspended mass. As a result, the tension in the rope will vary along its length. By contrast, for a light rope we may assume constant tension throughout the rope.
 
 
 
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