Yes, yet another blog on floating things. :P Of course, this doesn't mean that I haven't done 2 days worth of physics hw due to 21 hours of robotics competition, 4ish hours of band concert, almost 3 hours of an activity at the zoo I went to with my family, 3ish hours of dinner/partying after the robotics competition, and 20 hours of sleep in 3 days in my attempt to catch up on sleep. Which leaves about 11 hours for hw and eating... >< Missing school = pain...
Anyway, while washing dishes, I realized that the floating sponge meant that the buoyant force of the sponge was equal to the weight of the sponge itself. If I pretend that the sponge mass is 0.25 kg (I hope it weighs significantly less than that, but I'm too lazy to do the math with a stranger number. And I'm not about to weigh the sponge.), then it's weight in newtons is 2.45 newtons downward. This means that the buoyant force is also 2.45 newtons. If the buoyant force is equal to density times the acceleration of gravity times the volume of fluid displaced, and the density of water is 1000 kg/m^3, then you can find the volume of the sponge. This volume would be 2.5e-4 m^3. (Amazingly, this is reasonable sized for a sponge.) The density of the sponge could also be found, since D = m/v. The density of the sponge is 10,000kg/m^3. This is a rather dense sponge. (Please ignore the plethora of bubbles in the picture...)
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