A spool is on a horizontal surface (with friction) and pulled to the right with a thread attached to the center of the spool, so that the spool rolls without slipping. The spool has a mass of M, moment of inertia I, and a radius of R. Requird:
a. What is the relationship between the magnitude of the force of tension and the force of friction?
b. What expressions relates the magnitudes of the translational acceleration of the spool's center of mass a and the spool's rotational acceleration about the center of mass a (recall the spool rolls without slipping on the surface).

Now that we have a feel for the state of the circuit in its steady state, let us obtain the expression for the current in the circuit as a function of time. note that we can use the loop rule (going around counterclockwise): e−vr−vl=0. note as well that vr=ir and vl=ldidt. using these equations, we can get, after some rearranging of the variables and making the subsitution x=er−i, dxx=−rldt. integrating both sides of this equation yields x=x0e−rt/l. use this last expression to obtain an expression for i(t). remember that x=er−i and that i0=i(0)=0. express your answer in terms of e, r, and l. you may or may not need all these variables. use the notation exp(x) for ex.