How many impacts would you expect to strike a 100m2 region in one hour during Earth’s formation, assuming that Earth grew to its present size in 10 million years from particles averaging 100 grams each? (Hint: Assume that Earth had its current radius of 6378km.) (Notes: The surface area of a sphere is 4pir2 ; 1yr=3.2x107 .) a. About 1300. b. About 13 . c. About 13,000. d. About 130

How many impacts would you expect to strike a 100m2 region in one hour during Earth’s formation, assuming that Earth grew to its present size in 10 million years from particles averaging 100 grams each? (Hint: Assume that Earth had its current radius of 6378km.) (Notes: The surface area of a sphere is 4pir2 ; 1yr=3.2x107 .) a. About 1300. b. About 13 . c. About 13,000. d. About 130