Sure, let's break this problem down step by step to find the average speed of the truck.
1. Determine the distance traveled in each hour:
- In the first hour, the truck travels at 60 km/h for 1 hour.
[tex]\[
\text{Distance in first hour} = 60 \text{ km/h} \times 1 \text{ hour} = 60 \text{ km}
\][/tex]
- In the second hour, the truck travels at 80 km/h for 1 hour.
[tex]\[
\text{Distance in second hour} = 80 \text{ km/h} \times 1 \text{ hour} = 80 \text{ km}
\][/tex]
2. Calculate the total distance traveled:
- Add the distances from both hours.
[tex]\[
\text{Total distance} = 60 \text{ km} + 80 \text{ km} = 140 \text{ km}
\][/tex]
3. Determine the total time taken:
- The truck travels for a total of 2 hours (1 hour + 1 hour).
[tex]\[
\text{Total time} = 1 \text{ hour} + 1 \text{ hour} = 2 \text{ hours}
\][/tex]
4. Calculate the average speed:
- The formula for average speed is the total distance divided by the total time.
[tex]\[
\text{Average speed} = \frac{\text{Total distance}}{\text{Total time}} = \frac{140 \text{ km}}{2 \text{ hours}} = 70 \text{ km/h}
\][/tex]
So, the average speed of the truck is \(70 \text{ km/h}\). This speed is already expressed in the SI unit for speed, which is meters per second (m/s), but since the given speed is in km/h, it's supposedly more relevant to the context of everyday road traffic speeds. However, if you need to convert it to m/s for academic purposes:
5. Convert \(70 \text{ km/h}\) to m/s:
- We use the conversion factor \(1 \text{ km/h} = \frac{1000 \text{ m}}{3600 \text{ s}} = \frac{5}{18} \text{ m/s}\).
[tex]\[
70 \text{ km/h} = 70 \times \frac{5}{18} \text{ m/s} \approx 19.44 \text{ m/s}
\][/tex]
Thus, the average speed of the truck is [tex]\(70 \text{ km/h}\)[/tex] or approximately [tex]\(19.44 \text{ m/s}\)[/tex].
