If wind blows at 35 m/s over a house with flat roof with the area of 120 m^2. a) what is the net force on the roof due to bernoulli's principle? b)if the roof is not attached to the walls, what minimum mass should it have in order to stay in place rather than get lifted by the force found in question (a)? use 10 m/s for g, express the answer in metric tons (1 metric ton = 1,000 kg), and estimate how many cars or light-duty truc

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form