The ratio of the output work to input force is the _ of the machine ?

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

What are similarities and differences between refraction, reflection, diffraction and absorption?

Asolid cylinder and a cylindrical shell have the same mass, same radius, and turn on frictionless, horizontal axles. the cylindrical shell has light-weight spokes connecting the shell to the axle. a rope is wrapped around each cylinder and tied to blocks of equal masses that are held the same height above the ground. both blocks are released simultaneously. the ropes do not slip. which block hits the ground first? or is it a tie?