I need help to convert 23.5 million nanometers to millimeters

Acertain flow of air (at stp) has a velocity distribution given by v i (in ft/s). if this flow is going through a 4 ft square area in the yz-plane (centered at the origin), what is the mass flow rate (in lbm/s)?

For a gate width of 2 m into the paper, determine the force required to hold the gate abc at its location.

How to increase the thermal officiency of an ideal simple rankino cycle? among these methods, which one is the best and why?