Which of the following would be an example of mechanical energy? Elastic Energy, Kinetic Energy, Gravitational Energy

Gravitational Potential Energy, Thermal Energy

Electric Potential Energy, Nuclear Energy, Kinetic Energy

Magnetic Energy, Elastic Potential Energy

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.