3 ms·
Starting from rest at a distance infinity, any object (regardless of it's own mass) necessarily undergoes a minimum increase in kinetic energy due to the gravit
by johnpmayer 13y ago
Starting from rest at a distance infinity, any object (regardless of it's own mass) necessarily undergoes a minimum increase in kinetic energy due to the gravitational potential of the mass of the target object (in this case the Earth, which has a known mass and so this is calculable). So I think the assumption is that the object isn't propelling itself away from the earth, and the object hasn't experienced any major competing gravitational forces inside the radius of the Moon's orbit.
Also, 11km/s isn't terribly quick on the celestial scale, I'd imagine.
- lutorm 13y agoWhat you say is true but most objects are not starting from rest at infinity. Things thrown up from the Earth, for example. It also neglects that there is an atmosphere...
- halter73 13y ago>Impact Velocity - This is the velocity of the projectile before it enters the atmosphere. The minimum impact velocity on Earth is 11 km/s. I think it's implied that the impacting objects come from outside the Earth-Moon System. Otherwise there would obviously be no minimum impact velocity.