Select the correct answer. which of these actions is an example of chemical weathering? o a. freezing water widens the cracks in rocks. ob. plant roots force their way into cracks in rocks and break them. oc. oxygen in air reacts with iron content in rocks, causing them to change color. od. strong winds peel soft rock away, leaving harder rock behind. reset next

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.

Acalorimeter uses the principle that thermal energy flows from hotter material to colder material until both reach the same