To determine the average speed and average velocity over the first 4 seconds, we need more information regarding the object's motion. Typically, the position function $x(t)$ would be given in terms of time $t$, such as a polynomial or other expression, so we can compute:

1. Average speed: This is calculated as the total distance traveled divided by the total time.
2. Average velocity: This is calculated as the displacement (change in position) divided by the total time.

If you're trying to solve a problem based on this list of answers, we would need the exact form of $x(t)$ to calculate these values.

However, from the given options, let's consider them:

• The answers seem to provide both average speed and average velocity, and the key differences are whether the quantities are positive or negative.
• Average speed should always be positive, as it represents the total distance covered.
• Average velocity can be negative, indicating the direction of the displacement.

If you have the position function $x(t)$, I can help compute the exact values. If not, I would recommend choosing "I don't know" since we can't calculate the values without more information.

Would you like to provide more information, or pick the option you think is best?

---

Here are 5 related questions to deepen your understanding:

1. What is the difference between distance and displacement?
2. How do you find average velocity when given a position-time graph?
3. Why is average speed always positive, but average velocity can be negative?
4. Can an object have zero velocity but non-zero speed at the same time?
5. How does acceleration affect both speed and velocity over time?

Tip: To calculate average velocity, always focus on the net displacement, not the total path distance!