I pull 8m of rope to lift a barrel with a weight of 300N a distance of 2m off the ground using a pulley system. Assuming there is no friction:

a) How much work did I do?

b) How much force must I have used to pull on the rope?

c) What is the Mechanical Advantage of my pulley system?

Is the alien theory a scientific claim? why or why not? just took the test it was , : " the alien theory is not a scientific claim because it is not based on valid data, there is no evidence to support it, and it does not come from a reliable source."

What is the measurement of how fast an object moves relative to a reference point?

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.