What it means to say that energy is conserved as a ball fall towards ground

The image shows a pendulum in simple harmonic motion the pendulum starts at a and swing to e

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.

Slab pull” is a type of tectonic plate movement that occurs due to the forces of mantle convection and results in the subduction of the lithosphere true or false