Trying to answer 1 abcd Thank you Consider a spherical comet

Consider a spherical comet 2 kilometers in diameter with a mass of 5.25 Times 10^12 kg. Further assume that it crashes into Earth at a speed of 30,000 m/s (or 67,000 miles per hour) at an angle of 90 degrees to the surface (i.e., direct). What is the total kinetic energy of the impact in joules? (Show your work). Using the Purdue Impact Earth App on the internet: calculate how far away (in miles) from the impact that you would need to be in order to survive the thermal radiation of the impact (i.e., such that the body would receive only 2nd degree bums). You only need to be accurate to within 100 miles. At this distance, describe the damage in terms of the seismic activity, the air blast, and the ejecta. A VERY large nuclear weapon can release 1 Times 10^17 Joules of energy. How many nuclear bombs would it take to release as much energy as this comet impact? Do this many nuclear bombs exist on Earth (use Google/Wikipedia to come up with an estimate, cite your references).

Solution

a) KE = mv^2 /2 = 5.25e+12*(3e+4)^2 /2 = 23.625e+20 J

b) ata a distance of 1km ( less thana a mile)

Thermal radiation:

little vaporization occurs; no fireball is created, therefore, there is no thermal radiation damage.

c) seismic activity:

No seismic shaking, Ritcherscale magnitude = -6.1, seismic shaking felt only after 200 ms

Air Blast : The air blast at this location would not be noticed. (The overpressure is less than 1 Pa)

Ejecta : Most ejecta is blocked by Earth\'s atmosphere.

d) Total KE release = 23.625 e+20 J

Nuclear bomb = 1.0 e+17 J

       equivalent nuclear bombs = 23625