10) A 280 kg medium grand piano is resting on an 18° inclined plane. In order to help get the piano up the plane you attach a rope to the piano and run it through a pulley system as
shown below. If the coefficient of static friction between the piano and the floor is 0.55,
with what force will you have to push to make the piano start to slide?

What is the momentum of a 2 kg object moving at 15 meters per second

1. jay fills a wagon with sand (about 20 kg) and pulls it with a rope 30 m along the beach. he holds the rope 25° above the horizontal. the rope exerts a 20-n tension force on the wagon. how much work does the rope do on the wagon?

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.