1.The intensity of Na light passing through a gold film wasmeasured to be about 15% of the incoming light. What is thethickness of the gold film? ( λ=589 nm; k=3.2).
2.The large, newly planted tree is kept from tipping over in a windby use of a rope that is tied to a low branch at a 45 degree anglefrom the ground. It is assumed that the sandy soil cannotsupport any moment about the center of the soil ball, point A which is directly below the trunk. the lowest tree branches are 2 mfrom the ground. Estimate the tension in the rope if the wind is 80 km/hr.