What does it mean when a problem says massless pulley?

[Sniperman724]

What does it mean when a problem says "massless pulley?"

I am just curios about what it means, does it mean that the pulley doesn't bear any friction that works against a whole pulley system?

 

[Bob S]

usually it means that it has no moment of inertia.

Bob S

 

[sophiecentaur]

It's the same sort of concept as, when you do electrical calculations, you assume wires have no resistance, capacity or inductance. It gives you a chance to get the principle of the situation without bringing in a needless number of extra variables.

 

[Sniperman724]

Oh, okay, thank you very much!