Someone me with number 5. no idea what it is.

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?

Which process transfers heat from inside earth to its surface? convection currents in mantle pulling away of tectonic plates drawing in of tectonic plates convection currents in crust

A40 kilogram skier starts at the top of a 12 meter high slope. at the bottom, she is travelling 10 meters per second. how much energy does she lose to friction