24. An elevator is moving vertically up with an acceleration a. The force exerted on the floor by a passenger of mass m is (a) mg (b) ma (c) mg - ma (e) none of these (d) mg + ma

Awater slide of length l has a vertical drop of h. abby's mass is m. an average friction force of magnitude f opposes her motion. she starts down the slide at initial speed vi. use work-energy ideas to develop an expression for her speed at the bottom of the slide. then evaluate your result using unit analysis and limiting case analysis. express your answer in terms of the variables h, m, l, vi, f and appropriate constants. vf v f

If you wanted to move an electron from the positive to the negative terminal of the battery, how much work w would you need to do on the electron? enter your answer numerically in joules.

The first law of thermodynamics is as follows: ∆u=q-w , which means in a system is equal to added, minus done by the system. the units for these variables are in .