Actually they just said it is 4 years at the maxinmum
The acceleration of a different speck of dust is 40 m/s.
Since the radius is been given as double and angular velocity will be constant, we can calculate the centripetal acceleration as
a = (2r)ω²
If we substitute the given values of r= 2r , and ω²= 20m/s.
Then we have

Therefore, acceleration of a different speck of dust is 40 m/s.
<h3>What is centripetal acceleration?</h3>
centripetal acceleration can be regarded as acceleration of a body that is traversing a circular path.
CHECK THE COMPLETE QUESTIONS;
A speck of dust on a spinning dvd has a centripetal accelera- tion of 20 m/s2.
a. what is the acceleration of a different speck of dust that is twice as far from the center of the disk?
Learn more about centripetal acceleration at;
brainly.com/question/6217221
Rollie Tremaine is the one boy that Jerry and the others did not want to get a Grover Cleveland card.
________________________________________________
The hours it takes Kristen to travel the same distance Marian travelled is 19.5 hours.
The average speed of Marian is 65 miles per hour for 15 hours. Therefore, her distance travelled can be calculated as follows:
speed = distance / time
Therefore,
distance = time × speed
distance = 15 × 65
distance = 975 miles
Kristen travelled at an average speed of 50 miles per hour. Kristen covers the same distance with Marian. Therefore, the hours it takes Kristen to travel the same distance Marian travelled can be calculated as follows:
speed = distance / time
time = distance / speed
time = 975 / 50
time = 19.5 hours
learn more on average speed here: brainly.com/question/3267782?referrer=searchResults