Astudent places a 12-gram cube of ice inside a container. after six hours, the student returns to observe the contents of the container. which sentence suggests that the container is an open system? oa. the container contains 12 grams of liquid water and no ice. ob. the container contains 12 grams of ice and no liquid water. oc. the container contains 8 grams of liquid water and no ice. the container contains 8 grams of ice and 4 grams of liquid water. od. o e. the container contains 8 grams of liquid water and 4 grams of water vapor. reset next

Asmall amount of a solid is added to water. the observation made after fifteen minutes is shown in the figure. which of these solids has been probably added to water? a) oil b) sand c) sugar d) wood chips

Hot air balloons float in the air because of the difference in density between cold and hot air. in this problem, you will estimate the minimum temperature the gas inside the balloon needs to be, for it to take off. to do this, use the following variables and make these assumptions: the combined weight of the pilot basket together with that of the balloon fabric and other equipment is w. the volume of the hot air inside the balloon when it is inflated is v. the absolute temperature of the hot air at the bottom of the balloon is th (where th> tc). the absolute temperature of the cold air outside the balloon is tc and its density is ďc. the balloon is open at the bottom, so that the pressure inside and outside the balloon is the same. as always, treat air as an ideal gas. use g for the magnitude of the acceleration due to gravity.

Select the correct answer. which phrase correctly describes temperature? o a. average rotational kinetic energy of the particles in an object o b. average energy of the particles in an object c. average translational kinetic energy of the particles in an object od. all energy possessed by the particles in an object