Answer:
Explanation:
You have to declare which way is plus -- up or down. I will use down.
vi = - 2.85 The balloon is going up. That is the minus direction.
a = 9.81
d = 2.50 meters distance in this case is from the object to the ground.
d = vi*t + 1/2 a t^2
-2.50 = -2.85*t + 1/2 * 9.81 * t^2
-2.50 = -2.85*t + 4.905 * t^2 transfer the left to the right.
-4.905 t^2 + 2.85*t + 2.50 = 0
Use the quadratic formula to solve for t.
It turns out that t = 1.06
Answer:
t = 160 minutes
Explanation:
Given that,
Distance of Uranus from Sun is
We need to find the time taken by the light to go from sun to Uranus if the velocity of light is constant in free space and it is equal to c.
So,
Since, 1 minute = 60 seconds
t = 160 minutes
So, 160 minutes is taken by the light.
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! ^ ^
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