Given a plane electromagnetic wave of frequency f = 100 mhz propa- gating in wood for which material parameters are: fls = 1; er = 3; 0 = 10-s/m. (a) show that wood "qualifies" as a low-loss medium; (b) determine the attenuation coefficient a; (c) determine the distance over which the wave is attenuated by 1 db; (d) determine the phase constant b; (e) determine the propagation velocity vp; (f) determine the intrinsic impedance ne

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?

Abird flies directly overhead from where you stand at an altitude of 300.0 m and at a speed horizontal to the ground of 20.0 m/s. the bird has a mass of 2.0 kg. the radius vector to the bird makes an angle \thetaθ with respect to the ground. the radius vector to the bird and its momentum vector lie in the xyxy-plane. what is the bird’s angular momentum about the point where you are standing?

Explain what will happen if decomposers were apsent from a forest ecoysystem.