Why do objects made from different materials develop an electric charge when rubbed together? What is this method of charging called? Use a diagram to illustrate your answer.

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.

Juju.01) 5 geologic events a group of students designed an experiment in an ice rink to represent the solar system. the steps of the experiment are listed below. 5: geologic events 1. choose a student to represent the sun. the planets are represented by two tennis balls. 2. ask the student to hold the tennis balls in each palm and spin on the ice with arms stretched out. 3. ask the student to draw in the arms after about 10 spins. 4. observe the student's arms rotate faster when they are closer to the body. 05 geologic events enors) the experiment most likely demonstrates that (2 points) 07 discussion-based sessment/module planets exert gravitational force on the sun the sun exerts gravitational force on the planets 3.07 discussion-based ssessment speed of a planet depends on its distance from the sun new version available! (3.0.119) get it now submit 18.07: module exam description

In which region is the substance in both the solid phase and the liquid phase? 1 2. 3 4 mark this and return save and exit next