Scientists generally agree that earth is getting warmer due to what's called the greenhouse effect. a greenhouse used for plants stays warm because sunlight and heat coming through the glass roof are mostly trapped. the heat doesn't radiate back into the atmosphere because it's partly trapped by the glass. something like that happens on earth. the atmosphere acts like a blanket that keeps the sun's heat from leaking away into space.
7. the main conclusion you can draw from this paragraph is

The great sandini is a 60.0-kg circus performer who is shot from a cannon (actually a spring gun). you don’t find many men of his caliber, so you him design a new gun. this new gun has a very large spring with a very small mass and a force constant of 1100 n/m that he will compress with a force of 4400 n. the inside of the gun barrel is coated with teflon, so the average friction force will be only 40.0 n during the 4.00 m he moves in the barrel. at what speed will he emerge from the end of the barrel, 2.50 m above his initial rest position?