at sea level, the atmosphere has a density of 1.3kg/m^3. calculate the height of the atmosphere required to produce the average sea level pressure of 100kpa. why is the actual height much greater? g=10N/kg

During cooling, the kinetic energy of the molecules falls. why does this happen? a.the motion of the molecules increases. b. the motion of the molecules slows down. c.the van der waals forces between molecules decrease d. the forces of attraction between the molecules are overcome.

Aproton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?

Find an expression for the electric field e⃗ at the center of the semicircle. hint: a small piece of arc length δs spans a small angle δθ=δs /r, where r is the radius. express your answer in terms of the variables q, l, unit vectors i^, j^, and appropriate constants.