Recent content by fi245

yes of course, but the friction is different on different parts of the block. in the front edge, the butter comes in touch with "new" rooftop surface, where the friciton is at maximum, and on the other hand behind this front edge the butter has already melted a bit ->reduces the friction...

^^yes, that's how we thought the coefficient would reduce. in this problem, we are not taking account when the movement starts, but when it is already moving, so the time starts when the butter has moved a small distance dx. at this point, the small part of the butter (dx) has the original...

to clarify, when the piece moves, the front edge gets in contact with the untouched surface of the roof. The decrease in the friction face starts at the time when the piece touches the warm roof and begins to melt. And so the friction is dependant on both time and place.

Homework Statement A piece of butter is sliding down a warm roof. It is known, that on contact, the friction decreases to one tenth per 5 seconds. Not taking into count the fact that the mass reduces due to melting, how can you create the equation for the changing friction, that takes into...