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3 years ago

Which elements do hydrogen fuel cells combine to produce electricty

1 answer:

3 0

A fuel cell combines hydrogen and oxygen to produce electricity, heat, and water. Fuel cells are often compared to batteries. Both convert the energy produced by a chemical reaction into usable electric power.

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A city located on the coast of North America has warmer winters and cooler summers than a city at the same elevation and latitud

Vesna [10]

I don't like any of those choices. But if you absolutely have to pick your answer
from this list, then it has to be 'D'.

The ocean is an enormous storage vessel for heat. It gets heat from the air in
the Summer ... which somewhat cools places near the coast ... and it releases
heat into the air during the Winter ... which warms places near the coast.

So I guess it's true that ocean surfaces change temperature more slowly than
land surfaces do, and they influence the land nearby in the process. But this
ignores the reason for the slow changes in ocean surface temperature. It's a
lot like saying that the loud noise produced by a race car is the result of the
car's ability to appear in a far different location after a short time.

5 0

3 years ago

If the direction of the position is north and the direction of the velocity is up, then what is the direction of the angular mom

Kay [80]

Answer:

the direction of angular momentum = EAST

Explanation:

given

Direction of position = r = north

Direction of velocity = v = up

angular momentum = L = m(r x v)

where m is the mass, r is the radius, v is the velocity

utilizing the right hand rule, the right finger heading towards the course of position vector and curl them toward direction of velocity, at that point stretch thumb will show the bearing of the angular momentum.

then L = north x up = East

6 0

3 years ago

You can make the current in a circuit smaller by?

scZoUnD [109]

Decreasing the amount of current flowing through the circuit by using a 5 volt battery instead of a 10 volt battery.

3 0

3 years ago

Read 2 more answers

What is the area of soft cartilage where bone growth occurs

VladimirAG [237]

The area of <span>the epiphyseal plate belonging from a soft cartilage is where bone growth usually begins. The production of bones inside this tissue is due to a cell division by mitosis. In addition, this process of producing bone material to replace old bone structures is called ossification.</span>

6 0

3 years ago

You're driving down the highway late one night at 20 m/s when a deer steps onto the road 39 m in front of you. Your reaction tim

miss Akunina [59]

Answer:

a) 10.8 m

b) 24.3 m/s

Explanation:

In order to get the total distance traveled since you see the deer till the car comes to an stop, we need to take into account that this distance will be composed of two parts.
The first one, is the distance traveled at a constant speed, before stepping on the brakes, which lasted the same time that the reaction time, i.e., 0.5 sec.
We can find this distance simply applying the definition of average velocity, as follows:

$\Delta x_{1} = v_{1o} * t_{react} = 20 m/s * 0.5 s = 10 m (1)$

The second part, is the distance traveled while decelerating at -11 m/s2, from 20 m/s to 0.
We can find this part using the following kinematic equation (assuming that the deceleration keeps the same all time):

$v_{1f} ^{2} - v_{1o} ^{2} = 2* a* \Delta x (2)$

where v₁f = 0, v₁₀ = 20 m/s, a = -11 m/s².
Solving for Δx, we get:

$\Delta x_{2} = \frac{-(20m/s)^{2}}{2*(-11m/s)} = 18.2 m (3)$

So, the total distance traveled was the sum of (1) and (3):
Δx = Δx₁ + Δx₂ = 10 m + 18.2 m = 28.2 m (4)
Since the initial distance between the car and the deer was 39 m, after travelling 28.2 m, the car was at 10.8 m from the deer when it came to a complete stop.

We need to find the maximum speed, taking into account, that in the same way that in a) we will have some distance traveled at a constant speed, and another distance traveled while decelerating.
The difference, in this case, is that the total distance must be the same initial distance between the car and the deer, 39 m.
⇒Δx = Δx₁ + Δx₂ = 39 m. (5)
Δx₁, is the distance traveled at a constant speed during the reaction time, so we can express it as follows:

$\Delta x_{1} = v_{omax} * t_{react} = 0.5* v_{omax} (6)$

Δx₂, is the distance traveled while decelerating, and can be obtained using (2):

$v_{omax} ^{2} = 2* a* \Delta x_{2} (7)$

Solving for Δx₂, we get:

$\Delta x_{2} = \frac{-v_{omax} ^{2} x}{2*a} = \frac{-v_{omax} ^{2}}{(-22m/s2)} (8)$

Replacing (6) and (8) in (5), we get a quadratic equation with v₀max as the unknown.
Taking the positive root in the quadratic formula, we get the following value for vomax:
v₀max = 24.3 m/s.

6 0

3 years ago