My auestion is ! Write the value and unit of gravitational constant G in SI units?
Give me a answer for a short question !

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

Which component of the earth’s atmosphere is decreased due to photosynthesis?