what mechanical advantage does a hydraulic press punching holes in a metal sheet with a force of 800 N and using only 200 N and provide your answer as a ratio ​

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?

Engines for propeller-driven aircraft are limited in their maximum rotational speed by the fact that the tip speed of the propeller must not approach the speed of sound in air (mach i). taking 6 ft as a typical diameter for a propeller of a light airplane and 1100 fils as the speed of sound, find the upper limit on the rpm (revolutions per minute) of the propeller shaft.

What practical value did astronomy offer to ancient civilizations?