Using the set-up seen here, ms. garcia places a golf ball between the globe and the flashlight. turning off the lights in the room, she shines a flashlight from behind the golf ball. the students observe the shadow of the golf ball falling on the globe. what is this setup trying to model?
a) a solar eclipse
b) the solar system
c) the idea of gravity
d) the surface of the moon

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.