Paul is pushing himself and his wheelchair up a slanted part of the sidewalk as shown below. image courtesy of usdot which two simple machines are being used by paul to move himself?

100c is waters boiling point

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.