Answer:
d. 37 °C
Explanation:
= mass of lump of metal = 250 g
= specific heat of lump of metal = 0.25 cal/g°C
= Initial temperature of lump of metal = 70 °C
= mass of water = 75 g
= specific heat of water = 1 cal/g°C
= Initial temperature of water = 20 °C
= mass of calorimeter = 500 g
= specific heat of calorimeter = 0.10 cal/g°C
= Initial temperature of calorimeter = 20 °C
= Final equilibrium temperature
Using conservation of heat
Heat lost by lump of metal = heat gained by water + heat gained by calorimeter
1. solve for y-dir
sy = v0yt - 0.5gt^2 where g = 9.81 m/s^2
14 = v0yt - 4.905t^2
vy = v0y - gt where vy = 0 at the top of height
0 = v0y - 9.81t
2 eqns, 2 unkns
i. 14 = v0yt - 4.905t^2
ii. 0 = v0y - 9.81t
solved
v0y = 1.689 m/s
t = 16.573 s
2. solve for x-dir
sx = 0.5t×(vx + v0x)
where vx = 0 m/s b/c it lands in the end
where t = 16.573×2 = 33.146 s b/c 16.573 seconds was until ball reached height, hence it must take twice as long to reach the ground
21 = 0.5×33.146*(0 + v0x)
v0x = 1.267 m/s
Now combine x & y components
v0 = sqrt(v0x^2 + v0y^2)
m/s
hence v0 = 2.112 m/s
I believe you're asking about Helium with two numbers to the left of it.
Once number is on top of the other.
The 4, which is on top, represents the atomic mass. Helium's atomic mass is 4.
The 2, which is on bottom, represents the number of protons (or atomic number). Helium's number of protons is 2.
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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