Question

1.

Part A Estimate the pressure needed to raise a column of water to the same height as a 40-m-tall pine tree. Express your answer to two significant figures and include the appropriate units

2.

A person wearing the shoes has a mass of 54 kg .

3.

A spherical balloon has a radius of 6.75 m and is filled with helium. The density of helium is0.179 kg/m3, and the density of air is1.29 kg/m3. The skin and structure of the balloon has a mass of 980 kg . Neglect the buoyant force on the cargo volume itself.

Answer 1

Part A p_0 = p times g times h given h = 40 m p = 1000 kg/m^3 g = 10 pressure, p = 4 times 10^5 p = 4 times 10^5 N/m^2 (2) part A pressure = Force/Area p_1 = 54 times 10/(0.45) times 10^- 4 p_1 = 12 times 10^6 N/m^2 part B pressure = 54 times 10/16 times 10^- 4 p_2 = 0.33 times 10^6 N/m^2 \r\n (3) m = 980 kg m = lift mass vg (p_1 - p_2) = (m + m) g v = 4/3 pi times (6.75)^3 p_1 = 1.29 kg/m^3 p_2 = 0.179 1430.5 = 980 + M m = 450.5 kg