An umbrella tends to move upwards on a windy day principally because
A) air gets trapped under the umbrella, warms, and rises.
B) air pressure is reduced over the curved top surface.
C) buoyancy increases with increasing wind speed.
D) all of these

Question

Quizplus · Accepted Answer

The principle reason an umbrella tends to move upwards on a windy day is due to the reduction of air pressure over its curved top surface, a phenomenon described by Bernoulli's principle. This principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.

An Umbrella Tends to Move Upwards on a Windy Day