I'm assuming your question refers to the train travels 81 km in 2 hours, as in that's the total distance covered versus the speed for those 2 hours, whereas the 90 km in 2 hours the second time around is the total distance not speed I would assume.
Now... if it was going 81 km for the first 2 hours and 90 km for the second 2 hours then the average speed would be the mean of these numbers, with that being 85.5 km. Though, I doubt that's your question.
With that said, 81 km covered by 2 hours and 90 km covered by 2 more hours. To acquire the km an hour average, we'll have to divide the distance by how many hours it traveled:
81 / 2 = 40.5
90 / 2 = 45
Meaning the train was going 40.5 km an hour for the first 2 hours and 45 km an hour for the second 2 hours. Now, to find the mean:
40.5 + 45 = 85.5 / 2 = 42.75
In-case you were wondering, the mean is the sum of all the numbers in a set, divided by the total amount of numbers in that set, take for instance:
3, 5, 9, 2, 1, 5. -> There are 6 numbers in this set.
3 + 5 + 9 + 2 + 1 + 5 = 25 -> 25 is the sum of these numbers.
25 / 6 = 4.2 (estimated) -> 4.2 is roughly the mean or average between the original set.
Anyhow, with that aside the average speed between this I would believe would be 42.75 km an hour. I hope that helps, have a great rest of your day! ^ ^
| | Ghostgate (Alter) | |
Answer:
Matter is made of atoms which are in turn made up of protons, nuetrons and electrons. Atoms come together to form molecules which is the building block for all matter.
Explanation:
I feel like this question is like What is the meaning of life. Matter is made up of Matter. i don't know man
Basing on the information given, we can calculate the new weight of the object by the following given:current weight = 20 Ng = 10m/s2
20N/4 = 5N
Thank you for your question. Please don't hesitate to ask in Brainly your queries.
The answer to this question would be B. 4J
Galileo saw that Venus went through phases just like the moon .