Calculating Avg Speed of Round Trip: What's Wrong?

  • Thread starter camboguy
  • Start date
  • Tags
    Speed
In summary, The average speed for the complete round trip is 55km/hr. The first 200km is covered at 90km/hr and the final 200km is covered at 50km/hr. To calculate the average speed, we use the formula: average speed = total distance travelled/total time. In this case, the total distance is 400km and the total time is 6.2 hours (2.2 hours + 4 hours + 1 hour for lunch break). Dividing 400km by 6.2 hours gives us an average speed of 55km/hr. The mistake made was only considering the time and distance for the final 200km, instead of the entire round trip.
  • #1
camboguy
36
0
ok here's the question then what i did so far.

Q> calculate the avg speed of a complete round trip in which the first 200km is covered at 90km/hr, followed by a one-hour lunch break, and final 200km is covered at 50km/hr.


What i tried> 200km/90kmphr then i got 2.2hr and then 200/2.2hr to get the avg speed, which was 90km.

then i did 200km/50kmphr then i got 4hr and then 200km/4hr and got 50km. then avg those speeds but i keep geting around 70 and the answer is supposed to be 55km/hr.

what am i doing wrong?
 
Physics news on Phys.org
  • #2
"and then 200/2.2hr to get the avg speed, which was 90km."

but you are missing first half with the second half?

average speed = total distance travelled/total time

so total dist = 400
and total time =2.2+4+1
 
  • #3
aaaa i see thank you
 
  • #4
ohh.. now I got it, what you were doing there.. "200/2.2"
I think it would have worked if they hadn't stopped for the break
 

1. What is the average speed for a round trip?

The average speed for a round trip is calculated by dividing the total distance traveled by the total time taken. This will give you the average speed for the entire round trip.

2. How do I calculate the total distance traveled?

The total distance traveled is the sum of the distances traveled during each leg of the round trip. For example, if you travel 100 miles to reach your destination and 100 miles to return, the total distance traveled is 200 miles.

3. What if I make stops along the way during the round trip?

If you make stops along the way during the round trip, you will need to divide the total distance traveled by the total time taken, including the time spent at the stops. This will give you the average speed for the entire round trip, including the time spent at the stops.

4. What if I encounter different speeds during different parts of the round trip?

If you encounter different speeds during different parts of the round trip, you will need to calculate the average speed for each leg of the trip separately. Then, you can take the overall average of these speeds to get the average speed for the entire round trip.

5. Is there a difference between average speed and average velocity for a round trip?

Yes, there is a difference between average speed and average velocity for a round trip. Average speed only takes into account the total distance traveled and the total time taken, while average velocity takes into account the displacement (distance and direction) of the object. Therefore, if the object travels back to the starting point, the average velocity will be zero but the average speed will not.

Similar threads

  • Introductory Physics Homework Help
Replies
9
Views
2K
  • Introductory Physics Homework Help
Replies
10
Views
6K
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
17
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
7
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
3K
  • Introductory Physics Homework Help
Replies
6
Views
2K
Back
Top