The basic barometer can be used to measure the height of a building. if the barometric readings at the top and the bottom of a buikding are 730 and 755 mmhg, respectively, determine the height of the building. assume an average air density of 1.25 kg/m^3. provide with a simple sketch and graph it (hydrostatic pressure).

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".