Problem Breakdown:

We are tasked with finding the velocity of an object that starts from rest and accelerates at a constant rate for a given time.

Key Information:

1. Initial velocity ($v_0$): $0 \, \text{m/s}$ (starts from rest).
2. Acceleration ($a$): $3.0 \, \text{m/s}^2$.
3. Time ($t$): $6.0 \, \text{seconds}$.
4. Formula for velocity under constant acceleration:
   $v = v_0 + a \cdot t$

Substitution:

$v = 0 \, \text{m/s} + (3.0 \, \text{m/s}^2)(6.0 \, \text{s})$ $v = 18.0 \, \text{m/s}$

Final Answer:

The velocity of the object at the end of $6.0 \, \text{s}$ is:
$\boxed{18.0 \, \text{m/s}}$

Would you like additional details or clarification? Let me know!

Here are 5 related questions for further exploration:

1. What would the final velocity be if the acceleration were $5.0 \, \text{m/s}^2$?
2. How would the velocity change if the object had an initial velocity of $2.0 \, \text{m/s}$?
3. What is the displacement of the object over $6.0 \, \text{s}$ under these conditions?
4. How does the time of acceleration affect the final velocity?
5. If the acceleration is halved, how does it affect the velocity after $6.0 \, \text{s}$?

Tip: Always identify whether the problem involves constant or changing acceleration before selecting a formula.