Question

mary is biking downhill. she notices that her shirt and hair begin to pull back on her and blow in the \wind\ that she is creating as she moves faster. this \wind\ is an example of which of the following forces that also acts on an airplane?

a. sound waves
b. gravity
c. wind - tunnel modeling
d. drag

Explanation:

Drag is a force that opposes the motion of an object through a fluid (like air). When Mary bikes downhill and feels the "wind" pulling on her shirt and hair, it's the drag force. Similarly, an airplane experiences drag as it moves through the air. Sound waves are related to vibrations and not the force described. Gravity is a downward - pulling force, not the force of air resistance here. Wind - tunnel modeling is a method to study aerodynamics, not a force.

Answer:

D. Drag