How to calculate the Impact of a meteor

Question

I am trying to add a dose of realism to a story I'm writing: imagine an invulnerable superman-like being that won't disintegrate at any point, weighing in at 349lbs, travelling at 86,000mph through the atmosphere and striking a rocky plain at that speed. How much energy would this release? Would this be comparable to a nuclear strike?

I tried to do my homework by using this tool (http://www.purdue.edu/impactearth/), but it doesn't allow me to put in the desired impact speed, assumes a meteor that small would break apart and so forth. Any help would be appreciated.

Answer 1

Well, if he doesn't slow down, then he'll hit the Earth at 86,000 mph. So,
$$KE = \frac {mv^2}{2}$$ $$KE = \frac {158.3 kg\times (38445 m/s)^2}{2}$$ $$KE = 1.17\times 10^{11} J$$ I have no idea how to calculate the size of the carter it creates.

Added:
Now for a calculated guess:
Assuming that half the energy is used to heat the ground and propel the debris away, the other half is used to start the ground moving.
Using the density of the crust of $2700 kg/m^3$, then about $2.17\times 10^7 m^3$ of dirt gets moved.
Lets start with a circle with a diameter of $500 m$, this give an area of $1.96\times 10^5 m^2$, and a depth of about $110 m$.
A $400 m$ circle will have a depth of about $172 m$.

BTW, have you seen Meteor Crater?