An electric bell is kept under a bell jar in which a vacuum has been created. slowly air is introduced in to the jar. what will happen to the sound of the electric bell? select one of the options below as your . a. it will increase until it reaches its maximum.. b. it will decrease until it stops.. c. it will not change.. d. it will increase and decrease periodically. e. it will decrease exponentially

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.