The electric field between two parallel plates has a magnitude of 180 n/c. the two plates are 2.5 cm apart. recall that the magnitude of the charge on an electron is 1.602 × 10-19 c. how much work is done to move an electron from the positive plate to the negative plate?
a. 4.0 × 10-21 j
b. 7.2 × 10-19 j
c. 4.5 j
d. 7200 j
pleasssee !

Idon’t quite understand this problem

Utah's great salt lake has an average salinity seven times higher than that of the oceans. very few multicellular organisms live in this harsh environment. an example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. these brine shrimp must available hint(s)utah's great salt lake has an average salinity seven times higher than that of the oceans. very few multicellular organisms live in this harsh environment. an example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. these brine shrimp must pump water back into their cells to counter its loss due to osmosisactively pump water back out of their cells to counter its inflow due to osmosissynthesize membranes that are impermeable to substances that upset osmotic balanceactively pump salt back out of their cells to counter its inflow due to osmosis

Abookcase has a mass of 38 kg and the coefficient of friction between it and the floor is 0.82 what is the maximum force of friction between the bookcase and the floor a 372n b 305n c 412n d 449n