How Do You Calculate the Retarding Force in a Pulley System?

[blah:p]

how do u calculate the retarding force of a pulley system. I have made the force/acceleration graph required, and now it is telling me to use it to calculate the retarding force as best as I can.

 

[kamerling]

Is the retarding force the same as friction? was any information given on friction or a
retarding force in you problem?