Acube of aluminum floats in a container partially filled with mercury (a) both the aluminum and mercury are at 20.0 c. what fraction of the cube is above the surface of the mercury? (numeric answer.) (b) the temperature of both the aluminum and the mereury is raised to 350 °c. what fraction of the cube is above the surface of a mercury? (numeric answer. (c) if the aluminum cube were 0.01 m on a side when the temperature is 20.0 °c, what is the length of one side after the temperature has been raised to 350 °c? (numeric answer)

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants