average speed during deceleration = 2.5*10^3 m/s
time is then 4 m/2.5*10^3 m/s = 1.6*10^-3 seconds to stop
a = - 5*10^3/1.6*10^-3 = -3.125*10^6 m/s^2
= - 3,125,000 m/s^2:)
It has been suggested, and not facetiously, that life might have originated on Mars and been carried to Earth when a meteor hit Mars and blasted pieces of rock (perhaps containing primitive life) free of the surface. Astronomers know that many Martian rocks have come to Earth this way. (For information on one of these, search the Internet for “ALH 84001”.) One objection to this idea is that microbes would have to undergo an enormous, lethal acceleration during the impact. Let us investigate how large such an acceleration might be. To escape Mars, rock fragments would have to reach its escape velocity of 5.0 km/s, and this would most likely happen over a distance of about 4.0 m during the impact.
1 answer
1 answer