1. Jun 2, 2005

josephcollins

Hi ppl. I have a short question. A meteorite of mass m has a velocity u=2.00*10^4 m/s when it is at an infinite distance from the earth. It eventually collides with the eath with a velocity v. Calculate v. given are the radius of earth(6.37*10^6m) and go=9.80Nkg^-1)

I used the argument that the change in kinetic energy is going to be equal to 0.5m(v^2-u^2) which also equals GMem/2Re which resolves to goRem/2. Equating and calculating gives 2.15*10^4m/s. Could someone verify that this is correct and that potential energy or total energy is not neglected in my reasoning? thanks, joe

2. Jun 2, 2005

Staff: Mentor

I don't see why you divided by 2. (The change in PE should equal $g R_e m$)

Last edited: Jun 2, 2005
3. Jun 2, 2005

DaveC426913

Wow! That meteorite had quite the bounce to it to achieve that high and fast of an arc, don't you think?

Or perhaps your prof meant meteor?

;)

4. Jun 2, 2005

Staff: Mentor

I'll bet the prof meant meteoroid on its way to becoming a meteorite. (If the meteoroid burns up--becoming a "shooting star"--then it would be a meteor.)

Regardless, that's one heck of a meteoroid to make it through the atmosphere with no apparent loss of mass.

5. Jun 5, 2005

curvedlogic

Most scenarios seem to imply that massive objects hitting our planet would be traveling at a speed that would give days if not weeks of warning.

Is there any reason that a meteor should not hit the Earth at a very high relative velocity? Even one traveling at 80% the speed of light would be difficult to see coming, and hence be something of a surprise!