Calculate the critical angle for a glass air surface, if a ray of light which is incident in air on the surface is deviated through 15°, when angle of incidence is 40°.

Sara is creating an experiment. her hypothesis states the following. if i increase the air in my tires, then i will get better gas mileage. if this is her hypothesis what column titles do we need in our date table? a. air pressure in tire (psi) and gas mileage (mph) b. air pressure in the atmosphere (psi) and gas mileage (mph) c. miles (m) and gallons per mile (g) d. old battery and new battery

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

An object's buoyant force and weight mean the same thing.a. trueb. false