There are two concentric conducting spherical shells with a dielectric between them. Their radii are 0.1 m and 0.2 m. There is a voltage between the two spheres such that the surface of the r = 0.1 m shell has a surface free charge density of p_sf =5 times l0^-8 C/m^2. On the surface of the dielectric adjacent to the r = 0.1 m conducting shell is a surface bound charge density of p_sb=-2 times 10^-8 C/m^2. Find E, D, and P throughout the dielectric. What is the dielectric constant of the dielectric?

Afoot bridge is made as a simple deck, 4 m long, with a cross section 2 m (wide) and 20 cm thick, and made of wood. the deck is supported at the two ends. the maximum load allowable on the bridge is 10 tons, provided it is uniformly distributed on the deck. to sense this load, a strain gauge is placed at the center of the bridge and its resistance is monitored. if the sensor has a nominal resistance of 350 s2 and a gauge factor of 3.6, what is the reading of the strain gauge at maximum load? the modulus of elasticity for the wood used in the construction is 10 gpa.