« previous next »

Author Question: The event horizon of a black hole is the point where _____. a. the mass of the black hole is ... (Read 86 times)

audie

  • Hero Member
  • *****
  • Posts: 532
on: Jul 27, 2018
The event horizon of a black hole is the point where _____.
 
  a. the mass of the black hole is concentrated in a singularity
 b. the accretion disk around the black hole contacts its surface
 c. the escape velocity equals the speed of light
 d. tidal forces ionize infalling gas
 e. an infalling particle reaches equilibrium with radiation pressure

Question 2

What was Eratosthenes's mathematical contribution to the history of astronomy, even though it was incorrect?
 
  a. He calculated the diameter of Earth by what he learned from travelers' itineraries.
 b. He estimated Earth's revolution rate by measuring the length of shadows casted on the surface.
  c. He determined that all the planets orbited Earth every 24 hrs.
 d. He attempted to calculate Earth's radius by utilizing the position of sunlight.
 e. He believed all of nature was underlain by musical principles.


amandanbreshears

  • Sr. Member
  • ****
  • Posts: 320
Reply #1 on: Jul 27, 2018
Answer to Question 1

c

Answer to Question 2

d


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
« previous next »
 

Did you know?

Egg cells are about the size of a grain of sand. They are formed inside of a female's ovaries before she is even born.

Did you know?

In 2010, opiate painkllers, such as morphine, OxyContin®, and Vicodin®, were tied to almost 60% of drug overdose deaths.

Did you know?

Stevens-Johnson syndrome and Toxic Epidermal Necrolysis syndrome are life-threatening reactions that can result in death. Complications include permanent blindness, dry-eye syndrome, lung damage, photophobia, asthma, chronic obstructive pulmonary disease, permanent loss of nail beds, scarring of mucous membranes, arthritis, and chronic fatigue syndrome. Many patients' pores scar shut, causing them to retain heat.

Did you know?

Blastomycosis is often misdiagnosed, resulting in tragic outcomes. It is caused by a fungus living in moist soil, in wooded areas of the United States and Canada. If inhaled, the fungus can cause mild breathing problems that may worsen and cause serious illness and even death.

Did you know?

It is believed that humans initially contracted crabs from gorillas about 3 million years ago from either sleeping in gorilla nests or eating the apes.

Black flies are blood-sucking insects who vector disease, like River Blindness, while feeding on hum Black flies are blood-sucking insects who vector disease, like River Blindness, while feeding on hum
Black Locust Black Locust
Star Map Eastern Horizon Star Map Eastern Horizon
Structure of a Schwarzschild (Nonrotating) Black Hole Structure of a Schwarzschild (Nonrotating) Black Hole
Calculation of body mass index. To determine your BMI, find the value for your height on the left ... Calculation of body mass index. To determine your BMI, find the value for your height on the left ...
The Method for Determining the Two-Point Discrimination Threshold The Method for Determining the Two-Point Discrimination Threshold
Video: How to make cDNA Animation

For a complete list of videos, visit our video library