This topic contains a solution. Click here to go to the answer

Author Question: How does a rocket launch upwards? Choose the statement that best describes why a rocket goes up. ... (Read 78 times)

JGIBBSON

  • Hero Member
  • *****
  • Posts: 538
How does a rocket launch upwards? Choose the statement that best describes why a rocket goes up.
 
  A) By expelling gas downwards, the rocket is propelled upwards.
  B) By expelling gas, the rocket loses mass; because it is lighter, it rises up.
  C) By expelling gas downwards, which pushes against the ground, the rocket is propelled upwards.

Question 2

In order for the cosmic microwave background to show hydrogen absorption lines at the redshift corresponding to the universe's age of 380,000 years, what condition would have been necessary?
 
  A) There would have needed to be even warmer hydrogen clouds (which would contradict the observation of a uniform temperature in all directions).
  B) There would have needed to be cooler hydrogen clouds (which would contradict the observation of a uniform temperature in all directions).
  C) There would have needed to be ionized hydrogen (which would contradict the idea that the CMB originates at the time the universe cooled enough for protons and electrons to combine, making neutral atoms).



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

pikon

  • Sr. Member
  • ****
  • Posts: 361
Answer to Question 1

A

Answer to Question 2

B




JGIBBSON

  • Member
  • Posts: 538
Reply 2 on: Jul 27, 2018
Excellent


ktidd

  • Member
  • Posts: 319
Reply 3 on: Yesterday
Great answer, keep it coming :)

 

Did you know?

The shortest mature adult human of whom there is independent evidence was Gul Mohammed in India. In 1990, he was measured in New Delhi and stood 22.5 inches tall.

Did you know?

According to animal studies, the typical American diet is damaging to the liver and may result in allergies, low energy, digestive problems, and a lack of ability to detoxify harmful substances.

Did you know?

All adverse reactions are commonly charted in red ink in the patient's record and usually are noted on the front of the chart. Failure to follow correct documentation procedures may result in malpractice lawsuits.

Did you know?

According to the National Institute of Environmental Health Sciences, lung disease is the third leading killer in the United States, responsible for one in seven deaths. It is the leading cause of death among infants under the age of one year.

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.

For a complete list of videos, visit our video library