This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: Why is an umbrella in danger of being turned inside out on a windy day? What will be an ideal ... (Read 86 times)

Mr.Thesaxman

  • Hero Member
  • *****
  • Posts: 514
on: Jul 29, 2018
Why is an umbrella in danger of being turned inside out on a windy day?
 
  What will be an ideal response?

Question 2

Which is greater, the buoyant force that acts on an elephant, or on a helium-filled party balloon? Explain why the balloon rises in air and the elephant doesn't.
 
  What will be an ideal response?


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

dreamfighter72

  • Sr. Member
  • ****
  • Posts: 355
Reply #1 on: Jul 29, 2018
Answer to Question 1

Answer: Because of the umbrella's curvature, air passes faster over its top than across its bottom. This produces a difference in forces, and like an airplane wing, experiences lift. This is in accord with Bernoulli's principle. The lift can turn or flip the umbrella inside out.

Answer to Question 2

Answer: The buoyant force exerted by the atmosphere on any body is equal to the weight of air displaced. Since an elephant has more volume, it displaces more air and has a greater buoyant force on it than the buoyant force on the smaller helium-filled balloon. Whether or not something rises has to do with the relative magnitudes of the buoyant force and the force due to gravity. Aha, the force of gravity on the elephant is enormously greater than the buoyant force on the elephant. So gravity wins and the elephant is pressed to the surface. But for the balloon, its weight is less than the small buoyant force it experiences. Buoyant force wins and the balloon rises.


Mr.Thesaxman

  • Member
  • Posts: 514
Reply 2 on: Jul 29, 2018
Excellent

steff9894

  • Member
  • Posts: 337
Reply 3 on: Yesterday
Thanks for the timely response, appreciate it

« previous next »
 

Did you know?

Vampire bats have a natural anticoagulant in their saliva that permits continuous bleeding after they painlessly open a wound with their incisors. This capillary blood does not cause any significant blood loss to their victims.

Did you know?

Asthma-like symptoms were first recorded about 3,500 years ago in Egypt. The first manuscript specifically written about asthma was in the year 1190, describing a condition characterized by sudden breathlessness. The treatments listed in this manuscript include chicken soup, herbs, and sexual abstinence.

Did you know?

Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.

Did you know?

The FDA recognizes 118 routes of administration.

Did you know?

In ancient Rome, many of the richer people in the population had lead-induced gout. The reason for this is unclear. Lead poisoning has also been linked to madness.

Cultures Ideal Body Types Cultures Ideal Body Types
One version of a bump cap is a molded plastic insert worn inside a regular cloth cap. One version of a bump cap is a molded plastic insert worn inside a regular cloth cap.
Headlights were turned off and the battery voltage quickly recovered to indicate 12.6 volts. Headlights were turned off and the battery voltage quickly recovered to indicate 12.6 volts.
A funnel helps in hearing if the electric fuel pump inside the gas tank is working. A funnel helps in hearing if the electric fuel pump inside the gas tank is working.
The Danger of Driver Fatigue The Danger of Driver Fatigue
For the circuit in Figure 1, assume ideal diodes. The peak inverse voltage is approximately For the circuit in Figure 1, assume ideal diodes. The peak inverse voltage is approximately
Video: hGH, Thyroid hormones & Aldosterone

For a complete list of videos, visit our video library