What does it mean if an experiment exhibits reproducibility?
the experimental conditions are simple and do not require a lot of materials.
the experimental conditions are always kept the same.
the results of the experiment are always accurate.
the same results are expected each time the experiment is done.

If an experiment exhibits reproducibility, it means that the same results are expected each time the experiment is done. 

It depends on the surface of the levels. the rougher the surface, the greater is the frictional force. for rougher surfaces, you would need to exert greater force to move the object. the concept is that, you must overcome the frictional force in order to bring the object into motion. this is the reason why we add lubricants to the joints so they could easily move. this answer was on