What is the fastest airplane?

PLEASE HELP! What is the approximate magnitude of the drag force on an airplane (such as a commercial jet)?

• 1a) What is the approximate magnitude of the drag force on an airplane (such as a commercial jet) traveling at 242 m/s through air with a density 1.1 kg/m3? b) Which of the following can be used effectively to solve this problem? Answer: The drag force on a sphere is proportional to the velocity squared and to the cross sectional area. c) Which of the following diagrams best shows the forces acting along the x-axis of the plane which is moving to the left at a constant speed? Answer: The drag force will point opposite the direction of the plane's motion. This is how the diagram looks like Thrust Fd <---------<AIRPLANE/------------> d) Choose the equation that is needed to determine the drag on the airplane Fdrag = ½ρAv^2 Estimates 2) What is a reasonable value for the cross sectional area of the airplane encountering the drag force? ________m^2 Calculations (use your estimates) 3) The airplane experiences what drag force? ________N (Please show all work and steps)

• Answer:

  1a) FD = (1/2)*ρ *v^2*CD*A then plug-and-chug FD is the force of drag, which is by definition the force component in the direction of the flow velocity, ρ is the mass density of the fluid, v is the velocity of the object relative to the fluid, A is the reference area, and CD is the drag coefficient — a dimensionless constant related to the object's geometry and taking into account both skin friction and form drag.