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

Author Question: How does a rocket launch upwards? Choose the statement that best describes why a rocket goes up. ... (Read 170 times)

JGIBBSON

  • Hero Member
  • *****
  • Posts: 538
on: Jul 27, 2018
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
Reply #1 on: Jul 27, 2018
Answer to Question 1

A

Answer to Question 2

B


JGIBBSON

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

sultana.d

  • Member
  • Posts: 320
Reply 3 on: Yesterday
Wow, this really help

« previous next »
 

Did you know?

Between 1999 and 2012, American adults with high total cholesterol decreased from 18.3% to 12.9%

Did you know?

The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.

Did you know?

People with alcoholism are at a much greater risk of malnutrition than are other people and usually exhibit low levels of most vitamins (especially folic acid). This is because alcohol often takes the place of 50% of their daily intake of calories, with little nutritional value contained in it.

Did you know?

Many people have small pouches in their colons that bulge outward through weak spots. Each pouch is called a diverticulum. About 10% of Americans older than age 40 years have diverticulosis, which, when the pouches become infected or inflamed, is called diverticulitis. The main cause of diverticular disease is a low-fiber diet.

Did you know?

According to the FDA, adverse drug events harmed or killed approximately 1,200,000 people in the United States in the year 2015.

Example of an Explanation of Benefits statement. Example of an Explanation of Benefits statement.
A typical bank statement. A typical bank statement.
Example of Reconciling a Bank Statement Cont. Example of Reconciling a Bank Statement Cont.
The physician and medical assistant will often work together to choose appropriate educational ... The physician and medical assistant will often work together to choose appropriate educational ...
How to choose the right payment plan with changing conditions (Question 1) How to choose the right payment plan with changing conditions (Question 1)
A bank statement shows a balance of $2,970.31 The check register of the account owner shows an ... A bank statement shows a balance of $2,970.31 The check register of the account owner shows an ...
Video: Contraction cycle of a sarcomere

For a complete list of videos, visit our video library