In the context of mechanical systems, what does the term efficiency mean? © Α. the factor by which a machine multiplies a force O B. the ratio of a machine's power to the force of its input OC. the rate at which a machine performs work OD the rate at which a machine consumes energy © E. the ratio of the work output of a machine to the work input

When the piston is at its highest position in the cylinder, it’s said to be at the is a hollow metal tube drilled into the metal engine block. the top of the cylinder is sealed by a metal cover called the in a gasoline-powered engine, the ignites the air-and-fuel mixture in the cylinder and causes it to burn. why is it critical for the upper and lower end sections of an engine to work perfectly together?