At the surface of the Earth, the Sun delivers an estimated 1.43 kW/m2 of energy. Suppose sunlight hits a 20.1

At the surface of the Earth, the Sun delivers an estimated 1.43 kW/m2 of energy. Suppose sunlight hits a 20.1 m by 33.7 m roof at an angle of 90.0°.

a) Estimate the total power incident on the roof

b) Find the radiation pressure on the roof. (Assume the roof is black and totally absorbs the sunlight!)

a) Power = 1.43 . 10^3 . 20.1 . 33.7 = 9.686 . 10^5 W

b) Radiation pressure = I / c ( for absorption ) = 1.43 . 10^3 / 3. 10^8 = 4.77 . 10^–6 Pa