16.4 Exercise 9

Suppose that $\overset{\rightarrow}{S}_{\text{avg}}$ for sunlight at a point on the surface of Earth is $\left(900 \text{W}/\text{m}\right)^{2}$. (a) If sunlight falls perpendicularly on a kite with a reflecting surface of area $0.75 \text{m}^{2}$, what is the average force on the kite due to radiation pressure? (b) How is your answer affected if the kite material is black and absorbs all sunlight?