the first law of thermodynamics states that when you do work on a system you are adding to the system. how does this feflect the law of conservation of energy

The density of gold is 19.3g/cm3. what is the volume of a 13 g gold nugget? ( density: d= m/v)

What tightening torque should be used for a hexagonal head screw (not split-bolt) on a 250 kcmil conductor?

This is important 1. what happens to the speed of molecules in water vapor when it condenses to form a liquid? (2 points) the molecules slow down. the molecules speed up. the molecules slow down and then speed up. the molecules speed up and then slow down. 2. how might human activities change to compensate for a decrease in water supplies? (2 points) humans might build a factory. humans might build drainage systems. humans might extract more water from the ground. human behavior does not change because of the water cycle. i'll be grateful if anyone can answer these 2 questions !