Question

Select the correct answer.
A body travels 10 meters during the first 5 seconds of its travel, and it travels a total of 30 meters over the first 10 seconds of its travel. What is its average speed during the time from t = 5 seconds to t = 10 seconds?
A.
2 meters/second
B.
3 meters/second
C.
4 meters/second
D.
5 meters/second
E.
6 meters/second

Answer 1

To find the average speed of the body during the time from \( t = 5 \) seconds to \( t = 10 \) seconds, we first need to determine the distance traveled during this interval.

1. The distance traveled in the first 10 seconds is 30 meters.
2. The distance traveled in the first 5 seconds is 10 meters.

To find the distance traveled from \( t = 5 \) seconds to \( t = 10 \) seconds:

\[
\text{Distance from } t=5 \text{ to } t=10 = \text{Distance at } t=10 - \text{Distance at } t=5
\]

\[
= 30 \text{ meters} - 10 \text{ meters} = 20 \text{ meters}
\]

The time interval from \( t = 5 \) seconds to \( t = 10 \) seconds is:

\[
\Delta t = 10 \text{ seconds} - 5 \text{ seconds} = 5 \text{ seconds}
\]

Now we can calculate the average speed:

\[
\text{Average speed} = \frac{\text{Total distance}}{\text{Total time}} = \frac{20 \text{ meters}}{5 \text{ seconds}} = 4 \text{ meters/second}
\]

Thus, the correct answer is:

C. 4 meters/second