5) Consider these two facts: (a) The Earth has been hit by as many impactors as the Moon and Mars. (b) The state of Virginia has a total land area of about 102,000 km2 . Calculate how many 5-km-sized craters have been formed in Virginia over the last 4 billion years. [Show your work.]

It may seem strange that the selected velocity does not depend on either the mass or the charge of the particle. (for example, would the velocity of a neutral particle be selected by passage through this device? ) the explanation of this is that the mass and the charge control the resolution of the device--particles with the wrong velocity will be accelerated away from the straight line and will not pass through the exit slit. if the acceleration depends strongly on the velocity, then particles with just slightly wrong velocities will feel a substantial transverse acceleration and will not exit the selector. because the acc