Mary is trying to determine the charge of an object in the lab. she observes that it is repelled by a positively charged rod. what can you say about the charge of the object? . a. the object id positively chargered b. the object is negatively charged c. the object has no change or d. the object has the equal number of positive and negative charges

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.