Their relative speed is the sum of 60 and 40 or 100km/hr. They will travel the 150km in 1.5 hrs. When two object approach each other, the closing speed is just the sum of the speeds, therefore, the closing speed is your case is 100kph. So they will meet in 1.5 hours.
I'm pretty sure this is A
When an object's atoms move faster, its thermal energy increases and the object becomes warmer.
-is made mostly of hydrogen and helium.
-will eventually run out of fuel and die.
-creates energy through nuclear reactions
Density is varying through the world’s oceans. The density of ocean water is not uniform.