What is going on in this world?

What layer of the atmosphere is directly above the troposphere?

Which atom or ion is the largest? a. k b. k+ c. ca d. ca2+ e. li

2pos suppose an object in free fall is dropped from a building. its starting velocity is 0 m/s. ignoring the effects of air resistance, what is the speed (in m/s) of the object after falling 3 seconds? give your answer as a positive decimal without units. answer here