We often see cracks on rocks and stones why?

At time t=0, a particle is located at the point (3,6,9). it travels in a straight line to the point (5,2,7), has speed 8 at (3,6,9) and constant acceleration 2i−4j−2k. find an equation for the position vector of the particle.

What part of the ear is names after tools, such as the hammer and the anvil?

What organization and environment is described above?