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2 years ago

What do wind turbines, hydroelectric dams, and ethanol plants have in common?

Physics

2 answers:

AURORKA [14]2 years ago

6 0

Option b is right that is All use generators to produce electrical current

olasank [31]2 years ago

5 0

Answer: B. All use generators to produce electrical current.

Explanation:

The wind, water and ethanol all are the examples of renewable sources of energy. These can be used to generate electricity. The kinetic energy of the blowing wind, free flowing water and liquid like ethanol can be used to generate mechanical energy in the turbine which can help in generating the electricity in the generator.

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A tennis ball bounces on the floor three times. If each time it loses 22.0% of its energy due to heating, how high does it rise

lesya692 [45]

Answer:

H = 109.14 cm

Explanation:

given,

Assume ,

Total energy be equal to 1 unit

Balance of energy after first collision = 0.78 x 1 unit

= 0.78 unit

Balance after second collision = 0.78 ^2 unit

= 0.6084 unit

Balance after third collision = 0.78 ^3 unit

= 0.475 unit

height achieved by the third collision will be equal to energy remained

H be the height achieved after 3 collision

0.475 ( m g h) = m g H

H = 0.475 x h

H = 0.475 x 2.3 m

H = 1.0914 m

H = 109.14 cm

6 0

2 years ago

Grain is pored into a silo to be stored for later use. Due to the friction between pieces of grain as they rub against eachother

MariettaO [177]

Answer:

3.1×10⁻¹¹ N

Explanation:

Use Coulomb's law:

F = k q₁ q₂ / r²

F = (9×10⁹) (6.0×10⁻¹⁰) (2.3×10⁻¹⁵) / (0.02 m)²

F = 3.1×10⁻¹¹

6 0

2 years ago

A 1.0 104 kg spacecraft is traveling through space with a speed of 1200 m/s relative to Earth. A thruster fires for 2.0 min, exe

aniked [119]

We are given information:
$m=1.0* 10^{4} kg \\ v=1200m/s \\ t=2min=120s \\ F = 25kN = 25000N$

If we apply Newton's second law we can calculate acceleration:
F = m * a
a = F / m
a = 25000 / 10000
a = 2.5 m/s^2

Now we can use this information to calculate change of speed.
a = v / t
v = a * t
v = 2.5 * 120
v = 300 m/s

Force is being applied in direction that is opposite to a direction in which space craft is moving. This means that final speed will be reduced.
v = 1200 - 300
v = 900 m/s

Formula for momentum is:
p = m * v
Initial momentum:
p = 10000 * 1200
p = 12 000 000
p = 12 *10^6 kg*m/s
Final momentum:
p = 10000 * 900
p = 9 000 000
p = 9 *10^6 kg*m/s

7 0

2 years ago

An inclined plane is made out of a short plank of wood. It is used to move a 300N box up onto a tabletop 1m above the floor. Wha

Ronch [10]

Answer:

The purpose of an inclinded plane is to make easier to move objects to a certain height.

The technology behind this is about the Work you need to use to move the object upwards. Basically, when we use an inclined plane, we are splitting the net force, making easier to move. All this means, the force needed to move the objecto up will be lower, due to the inclined plane.

So, if the force needed is lower, then the work is also lower, because the work done is defined as the product between the force applied and the distance traveled.

In addition, if we have a longer inclined plane, that means the force needed is even lower, beacuse the distance is increased, but the Work is the same, because it only depends on the initial and final point.

Therefore, in this case, the work would remain the same and the mechanical advantage would increase. As we said before, the work needed will be the same despite the force decreases, because the distance increases, remaining the work as a constant. And the mechanical advantage increases, because it's easier to move if the inclined plane is longer.

3 0

2 years ago

Read 2 more answers

Calculate the heat required when 2.50 mol of a reacts with excess b and a2b according to the reaction: 2a + b + a2b → 2ab + a2 g

Yuri [45]

Answer:

Q = 12.5 kJ

Explanation:

The expression to use to calculate Heat is:

Q = H° * n

Where:

Q: heat (J or kJ)

H°: enthalpy of reaction (kJ/mol)

n: moles

Now, as it was stated in the comments, the question is incomplete, and here is the missing part:

Given:

2A + B  A2B (1)

H° = – 25.0 kJ/mol

2A2B  2AB + A2 (2)

H° = 35.0 kJ/mol

With these two reactions, we can calculate the heat.

Now, with the above two reactions, we need to get the general reaction (The one the question is giving), so, let's use (1) and (2) and do the sum of them:

2A + B -------> A2B H°1 = -25 kJ/mol

2A2B --------> 2AB + A2 H°2 = 35 kJ/mol

Now, we sum both equations, we can see that one A2B cancels out with one A2B from equation 2, so, the equation gives:

2A + B + 2A2B -------> 2AB + A2

And the enthalpy, it's just summed:

H°3 = -25 + 35 = 10 kJ/mol

Now with this value we can calculate heat:

Q = 10 * 2.5 = 25 kJ

However, in the reaction we have 2A, so it's not 1:1 mole ratio, but instead is 1:2, so this result we have to divide it between 2 so:

Q = 25 / 2 = 12.5 kJ

3 0

2 years ago