Physics questions

br 3 g 4 g 12 g 56 g They are the same The oxygen has more atoms The hydrogen has more atoms There is not enough information to say hotter colder they have the same temperature the walls do work on the gas the average momentum of each gas particle increases in magnitude the number of gas particles increases the volume of gas decreases quadruples doubles is cut in half is cut to one fourth metal A metal B

they have the same density up down horizontal the pressure doesn 't change as you move in any of these directions 1 atm 2 atm 3 atm 4 atm the wood cube the aluminum cube Both cubes experience the same buoyant force The is not enough information to say raised tarpaulins of moving tracks the curve of a baseball the lift produced on airplane the floating of icebergs Extra Credit Lab

Prepare a glass with water and a needle (the thinner the better . Very carefully place the needle on the surface of water . You may need to use a small piece of tissue for this . Why is the needle floating

Carefully add into water small amount of liquid soap . What do you see and what is your explanation

Due to the phenomenon of surface tension , the needle floats on water . In other words the cohesive force that exists between the water molecules supports the needle and prevents it from sinking . This is also the reason , why insects are able to skip across the surface of a pond

On adding soap solution to water , a wetting agent , the soap molecules spread across the surface of the water and interpose themselves between the water molecules . This leads to a reduction in the cohesive force between the water molecules or in other words , there is a reduction in the surface tension of water to such an extent that that the surface can no longer support the needle , which consequently sinks...