Communities with cold winters often spread salt on roadways. salt lowers the melting point of water, which means slippery snow and ice will melt instead of building up on roads. while this does prevent car accidents, it poses certain problems. what is the most serious problem that could occur to local ecosystems due to road salt?
a
flooding from too much melting ice and snow

b
overpopulation because of fewer fatal accidents

c
damage to plant life because of excess salt in the soil

d
accidents involving deer and other animals that lick salt

why are construction sites considered major sources of water pollution?
a
they introduce high levels of salt into local water sources.

b
soil erosion rates accelerate dramatically, impacting water quality in streams and rivers.

c
they cause sinkholes to form, which pollute local water sources.

d
sawdust leaches into the soil, causing the water that runs into rivers and streams to be cloudy and full of particles.

In a thunderstorm, charge builds up on the water droplets or ice crystals in a cloud. thus, the charge can be considered to be distributed uniformly throughout the cloud. for the purposes of this problem, take the cloud to be a sphere of diameter 1.00 kilometer. the point of this problem is to estimate the maximum amount of charge that this cloud can contain, assuming that the charge builds up until the electric field at the surface of the cloud reaches the value at which the surrounding air breaks down. this breakdown means that the air becomes highly ionized, enabling it to conduct the charge from the cloud to the ground or another nearby cloud. the ionized air will then emit light due to the recombination of the electrons and atoms to form excited molecules that radiate light. in addition, the large current will heat up the air, resulting in its rapid expansion. these two phenomena account for the appearance of lightning and the sound of thunder. take the breakdown electric field of air to be eb=3.00ă—106n/c. part a estimate the total charge q on the cloud when the breakdown of the surrounding air is reached. express your answer numerically, to three significant figures, using ďµ0=8.85ă—10â’12c2/(nâ‹…m2) .

Apulley with mass mp and a radius rp is attached to the ceiling, in a gravity field of 9.81 m/s2 and rotates with no friction about its pivot.

Convection occurs when thermal energy is transferred by the movement of