Sentence Example: Blindness is an obstacle in most occupations.
The language barrier is usually the most difficult aspect.
Language primarily, followed by cultural.
The paperwork and Information Technology challenges.
Static friction is typically the most difficult type of friction to overcome because it requires the most force to initiate motion between two surfaces. Once an object is in motion, kinetic friction is usually easier to overcome because the surfaces are already moving relative to each other.
By far the most difficult drug, or class of drug, to overcome are the Benzo's. Shorter lasting ones are the worst, yet even those with longer half-lives can take several months to years to recover from.
The most difficult barrier was probably that New Mexico couldn't become a state for almost 62 years, this seems difficult because it seems like that's a very long time to try to become a state to just be denied and rejected year after year with no guarantee that your territory would every become a state.
water is the oldest physical barrier. the barrier can be easily overcome with modern modes of transportation. however, inhabitants of some islands risk their lives to overcome this barrier. for example, the communist island of Cuba lies 150 km from Florida. many Cuban citizens have tried the dangerous crossing to Florida in old or leaking boats. most have been picked up the U.S coast guard, only to be returned to Cuba. many have tragically drowned in he attempt. deserts are another physical barrier. other physical barriers include jungles, swamps, mountains, and the lack of transportation routes (roads). barriers can also be man-made. for example the Berlin wall in Germany. it was once a heavily guarded wall splitting Germany into two - west and east Germany. it didnt let anyone escape from east Germany to west Germany. the wall was finally torn down in Germany reunited as one country.
In order for a given liquid or solid to evaporate, a sufficient 'energy barrier' has to be overcome. As this barrier is different for almost all materials, the rate at which the liquid becomes a gas is most certainly different.
Of course, it was discrimination and slavery. But, in the U.S., we have overcome that issue. But in other countries people still, sadly, discriminate blacks. Peace over the world! :]
physical strength
Gross motor