Black holes cannot be seen. However, scientists think that black holes exist because of their effect on surrounding matter. Describe another force or phenomenon that cannot be seen directly. Give examples of the effects of this force on everyday objects.

Silica, sio2, is formed on silicon as an electrically insulating layer for microelectronic devices. silica is formed when silicon is exposed to o2 gas at an elevated temperature. at 900˚c, it takes 90 minutes for the oxygen to diffuse from the surface to form a 0.06 micron (0.06 x 10-6 m) thick layer of sio2 on

Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 12.0 u.

Naoki's bicycle has a mass of 10 kg. if naoki sits on her bicycle and starts pedaling with a force of 168 n, causing an acceleration of 2.8 m/s2, what is naoki's mass?