Answer: The answer is B
Explanation: It is staying in a steady speed position
We would have to search at least 5,000,000,000 (5 billion) stars before we would expect to hear a signal.
To find out the number of stars that we will need to search to find a signal, we need to use the following formula:
- total of stars/civilizations
- 500,000,000,000 (500 billion) stars / 100 civilization = 5,000,000,000 (5 billion)
This shows it is expected to find a civilization every 5 billion stars, and therefore it is necessary to search at least 5 billion stars before hearing a signal from any civilization.
Note: This question is incomplete; here is the complete question.
On average, how many stars would we have to search before we would expect to hear a signal? Assume there are 500 billion stars in the galaxy.
Assuming 100 civilizations existed.
Learn more about stars in: brainly.com/question/2166533
Answer:

Explanation:
As we know that the combination is maintained at rest position
So we will take net torque on the system to be ZERO
so we know that

here we will have

so we have

so we have


The mass of the aeroplane is 300,000 kg.
<h3>What is Newton's second law of motion?</h3>
It states that the force F is directly proportional to the acceleration a of the body and its mass.
The law is represented as
F =ma
where acceleration a = velocity change v / time interval t
Given is the aeroplane lands at a speed of 80 m/s. After landing, the aeroplane takes 28 s to decelerate to a speed of 10 m/s. The mean resultant force on the aeroplane as it decelerates is 750 000 N.
The force expression will be
F = mv/t
Substitute the values and we have
750000 = m x (80 -10)/ 28
750,000 = m x 2.5
m = 300,000 kg
Thus, the mass of the aeroplane is 300,000 kg.
Learn more about Newton's second law of motion.
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