As a body is projected to a high altitude above the earths surface, the variation of the acceleration of gravity with respect to altitude y must be taken into account. neglecting air resistance, this acceleration is determined from the formula a=− g 0 [ r 2 /(r+y ) 2 ] , where g 0 = 9.81 m/ s 2 is the constant gravitational acceleration at sea level, r = 6356 km is the radius of the earth, and the positive direction is measured upward. with what velocity does the particle strike the earth if it is released from rest at an altitude y0 = 800 km?

In a unit cell of fcc structure, indicate the position of one of the tetrahedral interstitial sites by plotting the corresponding tetrahedron. do the same for one of the octahedral interstitial sites (in a separate fcc unit cell). mark the positions of all the tetrahedral and octahedral interstitial sites in the unit cells. how many equivalent tetrahedral sites and how many equivalent octahedral sites are contained in a fcc unit cell, respectively. what is the coordination number for a tetrahedral site and what is the coordination number for an octahedral site?