A sailboat is traveling to the right when a gust of wind causes the boat to accelerate leftward at 2.5\,\dfrac{\text m}{\text s^2}2.5
s
2

m

2, point, 5, start fraction, start text, m, end text, divided by, start text, s, end text, squared, end fraction for 4\,\text s4s4, start text, s, end text. After the wind stops, the sailboat is traveling to the left with a velocity of 3.0\,\dfrac{\text m}{\text s}3.0
s
m

3, point, 0, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction.

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.