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:

Answer:
C. Nucleus
Explanation:
The nucleus, formed by a nuclear membrane around a fluid nucleoplasm, is the control center of the cell. Threads of chromatin in the nucleus contain deoxyribonucleic acid (DNA), the genetic material of the cell.
have a good day and here’s a funny comic just for fun! :)
Answer:
W = 500 J
Explanation:
Work is defined by
W = F . x
if we develop the dot product
W = F x cos θ
where is the angle between the force and the displacement, in this case the angle is zero, so cos 0 = 1
W = F x
indicate that each person applies a force of 500 N, so the total force is
F = 1000 N
let's reduce the distance to the SI system
x = 50 cm = 0.50 m
let's calculate
W = 1000 0.50
W = 500 J