[The Fourth Blog] Work, Energy, & Power.

When we hear the word work, we usually think of that place where our parents go while we're in school or, much more likely (being that we are such studious 'Iolani students), homework. To a physicist, though, work can be defined as displacement times force in the direction of displacement (W = FcosθΔx) or as a change in energy (W = E_f - E_i).

     I normally don't think much about walking up the stairs at home because it's something I do every day, but I thought twice about it today since such an action can be related to physics.  When I am standing at the bottom of the stairs, kinetic and potential energy are both zero (no velocity and no h). When I reach the top, though, both my kinetic and potential energy have changed and thus I have done work - little as it may be. To calculate my work, I find my total energy at the bottom (0 J) and subtract it from my total energy at the top (612 J), resulting in 612 J of work. Not much work, but work nonetheless...  (And probably a greater value than that representing the amount of homework I have accomplished thus far. Not good.) From this I can calculate my power (P = W/t), which comes out to be 266 W (or 0.357 hp).  Physics has redefined the meaning of work for me and has taught me about the relationship between work, energy, and power.   

         

I made it to the top. :]