In a local diner, a customer slides an empty coffee cup down the counter for a refill. The cup slides off the counter and strikes the floor at distance d from the base of the counter. If the height of the counter is h, (a) find an expression for the time t it takes the cup to fall to the floor in terms of the variables h and g. (b) With what speed does the mug leave the counter? Answer in terms of the variables d, g, and h. (c) In the same terms, what is the speed of the cup immediately before it hits the floor? (d) In terms of h and d, what is the direction of the cups velocity immediately before it hits the floor?
Unit 8 Notes Atmospheric Pressure -Pressure is a force/unit area vertical pressure is influenced by gravity - Surface pressure, the standard sea-level air pressure is 1013.25 mb (millibars =101.325 hectopascals), about 14.7 lb/in2. -Pressure lines on surface weather chart are called isobars, and are drawn at 4 mb intervals. -Force- weight of atmosphere pressing down on Earths surface -When air is sinking, pressure is higher -When air is rising, pressure is lower Measurement of Pressure: The Barometer -Invented by Torricelli, a liquid-in-glass barometer. Standard barometer uses mercury. -Standard sea-level pressure is 760 mm (29.92”) -Aneroid barometer, like altimeter in airplanes, uses partial vacuum instrument to measure pressure.