the weight of the air on the earth's surface is called buoyancy.
the weight of the air on the earth's surface is called buoyancy.
what is the weight of the air on the earth's surface called?
buoyancy
mars lost its magnetosphere 4 billion years ago, possibly because of numerous asteroid strikes, so the solar wind interacts directly with the martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer. both mars global surveyor and mars express have detected ionised atmospheric particles trailing off into space behind mars, and this atmospheric loss is being studied by the maven orbiter. compared to earth, the atmosphere of mars is quite rarefied. atmospheric pressure on the surface today ranges from a low of on olympus mons to over in hellas planitia, with a mean pressure at the surface level of . the highest atmospheric density on mars is equal to that found above earth's surface. the resulting mean surface pressure is only 0.6% of that of earth (101.3 kpa). the scale height of the atmosphere is about , which is higher than earth's, , because the surface gravity of mars is only about 38% of earth's, an effect offset by both the lower temperature and 50% higher average molecular weight of the atmosphere of mars.
mars
no matter how smooth the surface of an airfoil seems, any surface is rough on the scale of air molecules. air molecules flying into the surface bounce off the rough surface in random directions relative to their original velocities. the result is that when the air is viewed as a continuous material, it is seen to be unable to slide along the surface, and the air's velocity relative to the airfoil decreases to nearly zero at the surface (i.e., the air molecules "stick" to the surface instead of sliding along it), something known as the no-slip condition. because the air at the surface has near-zero velocity but the air away from the surface is moving, there is a thin boundary layer in which air close to the surface is subjected to a shearing motion. the air's viscosity resists the shearing, giving rise to a shear stress at the airfoil's surface called skin-friction drag. over most of the surface of most airfoils, the boundary layer is naturally turbulent, which increases skin-friction drag.
lift (force)