What is space-time? (15.1) Does light travel through space? Through time? Through space and time? (15.1) What would be the momentum of an object if it were pushed to the speed of light? (16.2) What effect does solar energy have on the mass of the sun? (16.3) Distinguish between pressure and force (19.1) Explain Archimedes principle. (19) Explain Pascal's principle (19)