Two students are canoeing on a river. While heading upstream, they accidentally drop an empty bottle overboard. They then continue paddling for 60 minutes, reaching a point 2.0 km farther upstream. At this point they realize that the bottle is missing and, driven by ecological awareness, they turn around and head downstream. They catch up with and retrieve the bottle (which has been moving along with the current) 5.0 km downstream from the turnaround point. (a) Assuming a constant paddling effort throughout, how fast is the river flowing? (b) What would the canoe speed in a still lake be for the same paddling effort?
Melodi Harfouche Chemistry 130 Dr. Yihui Yang 01/26/2017 Surface Tension Surface tension is a physical property Its definition is the energy required to increase the surface area by a unit amount It is only a property of liquids and results from the tendency of liquids to minimize their surface area Surface tension is determined by two things: o Intermolecular forcesthe stronger the intermolecular attractive forces, the higher the surface tension will be o Temperatureraising the temperature of a liquid reduces surface tension Viscosity The definition of viscosity is the resistance of a liquid to flow It is also a physical property When intermolecular forces increase, the liquid’s