I tried to help but couldn’t :)
Using derivatives, it is found that:
i) 
ii) 9 m/s.
iii) 
iv) 6 m/s².
v) 1 second.
<h3>What is the role of derivatives in the relation between acceleration, velocity and position?</h3>
- The velocity is the derivative of the position.
- The acceleration is the derivative of the velocity.
In this problem, the position is:

item i:
Velocity is the <u>derivative of the position</u>, hence:

Item ii:

The speed is of 9 m/s.
Item iii:
Derivative of the velocity, hence:

Item iv:

The acceleration is of 6 m/s².
Item v:
t for which a(t) = 0, hence:




Hence 1 second.
You can learn more about derivatives at brainly.com/question/14800626
Answer:
1) $283.50
2) 65.21 meters.
Step-by-step explanation:
Part 1)
We know that a spool of ribbon holds 6.75 meters.
A craft club buys 21 spools.
So, the total length of ribbon bought is:

Each meter costs $2. So, the total cost will be:

Part 2)
A spool holds 6.75 meters.
We bought 21 of them, so that total length we have is 141.75 meters.
The club used 76.54 meters.
So, the amount of ribbon that is left is represented by:

Subtract:

So, 65.21 meters of ribbon will be left.