If Keiji stands on a hilltop and holds a large sheet of lightweight fabric during a windy day, what will happen to the fabric when the wind starts blowing?

Respond very briefly.
The lightweight fabric in Keiji's hands will billow out and flutter in the direction the wind is blowing. This happens because the wind exerts a force on the flexible and low-mass material of the fabric, causing it to move along with the direction of the airflow. If Keiji is facing into the wind, the fabric will blow away from him. If the wind is coming from behind, the fabric will blow forward, away from Keiji's body. The fabric is acting like a sail, capturing the moving air on one side and creating pressure that pushes it along.