Which tool is used to see objects too small to be seen with the human eye?

Atown is considering building a biodiesel power plant that would burn biomass to generate electricity. which of the following correctly lists an advantage and a disadvantage of this project?

Which bonds are found inside a water molecule

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.