PHYSICS 3B Study Guide - Final Guide: Buoyancy, Thermodynamics, Plough
23 Nov 2015
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Fluids (8 points: a slab of ice floats on a freshwater lake. What minimum volume must the slab have for a. 60. 0 kg person to be able to stand on it without getting their feet wet? (4 points) The volume will be minimum if the entire slab is submerged. In that case, the buoyant force (upward) on the slab must exactly balance the weight (downward) of the slab and the person: Fb = v water g = wtot = v ice g + mpersong. V = mperson/( water ice) = (60. 0 kg)/(1000 kg/m3 917 kg/m3) = 0. 723 m3: a vertical straw sits in a bottle of water. What speed must you blow air across the top of the straw to make the water level in the straw rise by 2. 00 cm? (4 points) The air pressure inside the straw must be reduced by an amount equal to the pressure of a 2. 00 cm column of water.
