scientists have determined the composition of the lithosphere and asthenosphere but have struggled to discover much about the lower mantle (mesosphere). what are the compositions of the upper two parts of the mantle? why is it difficult for scientists to learn about the mesosphere? How could they try to gather more information about it?

(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)

The amount of potential energy possessed by an elevated object is equal to what?

The particles that are found in the nucleus of an atom are