I'm like 89% sure that the answer is C.
Answer:
a) 
Now we can replace the velocity for t=1.75 s

For t = 3.0 s we have:

b) 
And we can find the positions for the two times required like this:
And now we can replace and we got:

Explanation:
The particle position is given by:

Part a
In order to find the velocity we need to take the first derivate for the position function like this:

Now we can replace the velocity for t=1.75 s

For t = 3.0 s we have:

Part b
For this case we can find the average velocity with the following formula:

And we can find the positions for the two times required like this:
And now we can replace and we got:

<span>. Blue/violet have the shortest wavelengths so they will appear least raised. </span>
It would take about 4.8 years to travel from earth to Saturn.
<h3>How long would it take?</h3>
We know that speed is expressed as the ratio of distance to time. In this case, we are trying to know ow many years would it take to reach the planet Saturn travelling at 21 thousand miles per hour.
Given that;
Speed = 21 thousand miles per hour
time taken = ???
Distance = 887 million miles
Speed = distance/time
speed * time = distance
time = distance/speed
time = 8.87 * 10^8 miles/2.1 * 10^4 miles per hour
time = 4.22 * 10^4 hours
If 8.766 * 10^3 hours make 1 year
4.22 * 10^4 hours make 4.22 * 10^4 hours * 1 year/8.766 * 10^3
= 4.8 years
Learn more about Saturn:brainly.com/question/12181523
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