When water vapor is cooled, it reforms into water droplets. Why does this represent a conservation in mass

At an oceanside nuclear power plant, seawater is used as part of the cooling system. this raises the temperature of the water that is discharged back into the ocean. the amount that the water temperature is raised has a uniform distribution over the interval from 10° to 25° c. what is the standard deviation of the temperature increase?

The diagram shows four locations in the electric field of a positive point charge m. at which location is the electric potential the greatest.

Ajoint produces movement when its angle decreases. which type of movement is it?