Author Question: An umbrella has a tendency to move upward when it is windy principally because 1) moving air over ... (Read 26 times)

vicky · **on:** Jul 29, 2018

An umbrella has a tendency to move upward when it is windy principally because

1) moving air over the curved surface produces reduced pressure against its top.
2) air moves up into the bowl and pushes upward with increased pressure.
3) buoyancy increases with increasing wind speed.
4) the umbrella is simply pushed upward by the wind.

This effect was first accurately described by
5) Galileo.
6) Newton.
7) Bernoulli.
8) Einstein.
9) Archimedes.

Question 2

It would be easier to pull the hemispheres apart

1) when they are at sea level
2) if submerged several meters in water
3) if high above the clouds

because
4) external pressure on the hemispheres is lessened.
5) water serves as a lubricant.
6) the atmosphere exerts a pressure of 105 N/m2 on both hemispheres.