Question

An asteroid that slammed into Earth about 65 million years ago (low on the dinosaurs' hit parade) was estimated to be about 8 km in diameter and about 10^15 kg in mass. A) If a similar asteroid headed toward Earth now with a speed of 21 km/s, how much kinetic energy would it have? B) Compare this answer to the energy used by the US in one year (about 10^20 J) and discuss. Problems

Answer 1

KE = 1/2 mv^2 = 1/2 * 10^15 * 21000^2 = 1.05*10^19 J
Now compare and discuss

Answer 2

A) KE = 1/2 m v^2 = 1/2 * 1E15 kg * (2.1E4 m/s)^2 ≈ 1E23 J

B) about a thousand times annual US energy consumption

the largest man-made explosion was a 50 MT thermonuclear weapon
detonated by the Soviet Union in October of 1961 ... 2.1E17 J

the largest recorded explosion in human history was the Krakatoa volcano in Indonesia ... August, 1883 ... estimated at 8.4E17 J

Answer 3

oops. I forgot to evaluate v^2 ...