Changing rho 2 a wire with a circular cross section has radius 0.01 mm and is lying along the z axis from z=0 to z=0.40 m. the wire is made of an alloy that varies with its length in such a way that the resistivity is given by rho=4z2 ω⋅m, for z in meters. what is the resistance of this wire?

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.