Mr. nakamora wants to test the accuracy of an old balance in his classroom compared to a brand-new balance that he knows is accurate. he weighs an object on the old balance and finds it to have a mass of 15.6 grams. the same object weighs 15.9 grams on the brand-new balance.

what is the percent error between the old and new balance?

0.97%
1.29%
1.89%
2.29%

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.