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m_a_m_a [10]
2 years ago
13

Some fuel cells are powered by hydrogen. Scientists are looking into the decomposition of water (H2O) to make hydrogen fuel with

the help of the Sun’s energy. What challenge do scientists face with this task?
A.

Decomposing water requires a high activation energy.

B.

The Sun isn't a renewable resource.

C.

Decomposing water results in toxic byproducts.

D.

Scientists are uncertain what to do with the excess oxygen.
Physics
2 answers:
Sauron [17]2 years ago
6 0

Answer:

A. Decomposing water requires a high activation energy.

Explanation:

The leftovers of the division of the molecule of water would be Hydrogen that would be used as fuel, and oxygen which is necessary and its benefical for humans, so there would be no toxical residuals, and the residuals could be thrown to the air, so the most challenging thing that the scientist would face would be the fact that the molecule of water has a really strong bond between the oxygen and the two atoms of hydrogen, so it requires a really high activation energy.

mr_godi [17]2 years ago
5 0

A challenge scientists face with this process is the use of ultrathin iron oxide, to pull protons off water and produce hydrogen gas, which itself is a poor electrical conductor.

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A ball is thrown horizontally at a height of 2.2 meters at a velocity of 65m/s off a cliff. Assume no air resistance. How long u
slega [8]

The horizontal motion has no effect on the vertical drop.

From a drop, the distance the ball falls in 'T' seconds is

D = 4.9 T^2

so

2.2 = 4.9 T^2

T^2 = 2.2/4.9

T^2 = 0.449 sec^2

T = 0.67 second

8 0
2 years ago
01 – (Valor – 2,0) O maior campo de testes de veículos da América Latina, localizado na cidade de Indaiatuba (SP), tem forma cir
Scilla [17]

Answer:

a) Calcule a frequência em RPM

= 0.6 RPM

b) a velocidade escalar do carro em m/s.

= 20m/s

Explanation:

a) Calcule a frequência em RPM

A fórmula para calcular a frequência é: 1/T

onde T= Tempo (seconds)

T = 100s

A frequência = 1/100s

A frequência = 0.01Hz

em RPM

A fórmula para calcular a frequência em RPM =

1 Hz = 60RPM

0.01Hz =

A frequência em RPM = 0.01Hz × 60

= 0.6 RPM

b) a velocidade escalar do carro em m/s.

A fórmula para calcular a velocidade escalar = diâmetro ou distância (m) ÷ tempo (s)

Diâmetro ou Distância = 2.0km

Converter 2.0km para m

1 km = 1000m

2km =

2 km × 1000m

= 2000m

A velocidade escalar = 2000m ÷ 100s

A velocidade escalar = 20m/s

Answer:

a) Frequency in RPM

= 0.6 RPM

b) Scalar Velocity

= 20m/s

Explanation:

a) Frequently in RPM

Formula : 1/T

Where T= Time (seconds)

T = 100s

= 1/100s

= 0.01Hz

Frequency in RPM =

1 Hz = 60RPM

0.01Hz = 0.01Hz × 60

= 0.6 RPM

b) Scalar velocity

The formula = Diameter or Distance ÷ Time

Diameter or Distance = 2.0km

Convert 2.0km to m

1 km = 1000m

2km =

2 km × 1000m

= 2000m

Scalar Velocity = 2000m ÷ 100s

Scalar Velocity = 20m/s

8 0
2 years ago
A ladybug sits at the outer edge of a turntable, and a gentleman bug sits halfway between her and the axis of rotation. The turn
Cerrena [4.2K]

Answer:

e. Not enough information to determine

Explanation:

This question is incomplete. Here is the complete question with my solution afterwards;

A ladybug sits at the outer edge of a turntable, and a gentleman bug sits halfway between her and the axis of rotation. The turntable (initially at rest) begins to rotate with its rate of rotation constantly increasing.

What is the first event that will occur?(Assume non-zero frictional force and the same coefficients of friction for both bugs.)

a. The ladybug begins to slide

b. The gentleman bug begins to slide

c. Both bugs begin to slide at the same time

d. Nothing ever happens

e. Not enough information to determine

The centripetal force acting on a rotating body or bugs can be written as,

F=mrw^2

m= mass of the corresponding bugs

r= corresponding radial distance of each bug

w= angular speed of the turntable

The centripetal force tries to slide the bugs in an outward direction and it is directly proportional to the products of its mass and radial distance from the axis of rotation of the turntable

F ∝ mr

Since the radial distance from the axis of rotation of the turntable for each bug is given, but the mass is not given, the given information is therefore not enough to determine which bugs will slide first.

Option "e" is correct.

7 0
2 years ago
Read 2 more answers
A mover hoists a 50 kg box from the ground to a height of 2 m. What was the change in the box's energy
SSSSS [86.1K]

Answer:

980 J

Explanation:

The change in box's energy is equal to its change in gravitational potential energy:

\Delta U = m g \Delta h

where

m = 50 kg is the mass of the box

g = 9.8 m/s^2 is the acceleration due to gravity

\Delta h= 2m is the change in height of the box

Substituting numbers, we find

\Delta U = (50 kg)(9.8 m/s^2)(2 m)=980 J

3 0
2 years ago
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MrRa [10]

Explanation :

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So, the correct option is (b) "the severity of stochastic effects, such as cancer".

7 0
3 years ago
Read 2 more answers
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