help it's for my civics class

Answer:

[tex]\eta_{turbine} = 0.777 = 77.7\%[/tex]

[tex]\eta_{combined} = 0.728 = 72.8\%[/tex]

Explanation:

First we calculate the power input to the turbine. The input power will be equal to the potential energy of water per unit time:

Input Power = [tex]P_{in} = \frac{Work}{Time} = \frac{Potential\ Energy\ of\ Water}{t} \\P_{in} = \frac{(mass)(g)(height)}{Time} = (mass flow rate)(g)(height)\\\\P_{in} = (1500\ kg/s)(9.81\ m/s^2)(70\ m)\\P_{in} = 1.03\ x\ 10^6\ W = 1030\ KW[/tex]

Now, for turbine efficiency:

[tex]\eta_{turbine} = \frac{Mechanical\ Power\ Out}{P_{in}}\\\\\eta_{turbine} = \frac{800\ KW}{1030\ KW}\\\\\eta_{turbine} = 0.777 = 77.7\%[/tex]

for generator efficiency:

[tex]\eta_{generator} = \frac{Power\ Generation}{Mechanical\ Power\ Out}\\\\ \eta_{generator} = \frac{750\ KW}{800\ KW}\\\\\eta_{turbine} = 0.9375 = 93.75\%[/tex]

Now, for combined efficiency:

[tex]\eta_{combined} = \eta_{turbine}\ \eta_{generator}\\\\\eta_{combined} = (0.777)(0.937)\\\eta_{combined} = 0.728 = 72.8\%[/tex]

Answer:

5 years worth of work (aka all of the homework i currently have)

Answer:60 W

Explanation:

Answer:500

Explanation:

If two forces are acting on an object in the same  direction, then they will add up and the net force will be the sum of their magnitudes. Thus, the net force on refrigerator is 500 N.

Force is an external agent acting on a body to deform it or to change it form the state of rest or motion. There are various kinds of forces, such as gravitational force, frictional force, magnetic force etc.

If two forces are acting on a on an object in the same  direction, then they will add up and the net force will be the sum of their magnitudes. If they are acting from the opposite directions, they will cancel each other in magnitude and and the net force will be the subtracted value.

Here, both Allison and fred pulls the refrigerator from the same direction and the net force is the sum of  forces by each person. Therefore, the net force here is 300 + 200 = 500 N.

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Answer:

The answer is actually a. Cathode

Explanation:

Just took the quiz

In an electrolytic cell, the reduction occurs at the cathode. So, the correct option is a.

Reduction is defined as the process through which a reactant gain electrons during a chemical reaction.

Here,

An electrolytic cell is an equipment that uses electric current to drive a redox reaction.

Redox reactions are the type of reaction that involves the transfer of electrons between the reactants. That means, in redox reactions, both oxidation and reduction occurs. The reactant that gains the electrons is said to be reduced and the one that losses the electrons is said to be oxidized.

In an electrolytic cell, cathode is the positively charged electrode. So, electrons are attracted towards it, and as a result, the cathode gets reduced.

Hence,

In an electrolytic cell, the reduction occurs at the cathode.

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Answer:

The upthrust or buoyant force helps the duck doesn't sink.

For example, there is a duck which weighs 3 pounds and tree pints of water also weigh three pounds. In this case the volume of the duck is more than the volume of three pints of water, so the duck floats.

Hope it helps!<3

Answer:

Explanation:

Given parameters:

Weight of object  = 49N

Force applied = 12N

Unknown:

Acceleration of object  = ?

Solution:

The acceleration of the object is found by dividing the force by the weight;

 Acceleration  = [tex]\frac{12}{49}[/tex]   = 0.25m/s²

Answer: A woman moved her child from one place to another in a wagon

or A bird sat on a telephone wire

Explanation:

Answer:

photosynthesis

Explanation:

I just took the midterm and got it correct :))

PLZ MAKE BRAINLIEST, thank youuu <3

Answer:

68.2 Quadrillion meters

Explanation:

A lightyear is the distance that light travels in one year.

Speed of light is [tex]3*10^8\ m/s[/tex]

So light covers 300,000,000 meters in one second.

One year has 31536000 seconds so , light covers

[tex]9.461*10^{15}\ meters\ in\ one\ year[/tex]

so 7.2 light years is

[tex]7.2*(9.461*10^{15})\\6.82*10^{16}[/tex]

so 7.2 light years is

6.82 x 10^(16) meters or

68.2 Quadrillion meters

Answer:

143

Explanation:

Using one of the 3 fundamental equations in physics, y=vo*t+1/2gt^2, we can use this equation to find the total distance that was traveled.

Acceleration due to gravity is always 9.8m/s^2 and time is 5.4s, we also have no initial velocity.

Given this, we can plug in the known variables.

y=0t+1/2*9.8*5^2

simplify,

y=4.9*5.4^2

y=4.9*29.16

y=142.884m which we can round up to 143 meters

Final Answer: 143 meters

Answer:

u = 7.74 m/s and t = 1.82 s

Explanation:

Given that,

Harold threw a baseball 3 meters.

Harold is 2 meters tall.

The vertical distance = 3m

The final velocity at the maximum height is  0.

Let u is the initial velocity of the baseball. Using the first equation of motion to find it as follows :

[tex]v^2-u^2=2as[/tex]

Here, a = -g

[tex]v^2-u^2=-2gs\\\\u=\sqrt{2gs} \\\\=\sqrt{2\times 10\times 3} \\\\=7.74\ m/s[/tex]

He has thrown it with the speed of 7.74 m/s

Let t is the time taken by the ball to fall on the ground.

Harold is 2 meters tall. Using second equation of motion to find it.

u = -7.74 (as downward direction is taken as positive)

[tex]s=ut+\dfrac{1}{2}at^2\\\\2=-7.74t+5t^2\\\\t=1.82\ s[/tex]

Hence, this is the required solution.

30N

Natural reaction, the same force comes back to you

Answer:

it depends on if collision elastic or in elastic

if collision is elastic the the wall will also exert 30 N

Answer:

forever

Explanation:

Answer:Control S, Command S on MAC=Save

Answer:

d

Explanation:

Answer:

Earth absorbs heat from the sun.

Explanation:

This radiation is absorbed by greenhouse gases which then radiate energy into all directions including downwards and thereby trapping heat in the atmosphere.

Hope you have a good day :)

Answer:

The resistance of an ammeter should be low. This is because an ammeter is connected in series with the circuit for the measurement of electric current. In case, its resistance is high, then some amount of current may lost in heating it leading to the inaccurate reading. An ideal ammeter is one which has zero resistance.

Answer:

Bread contains energy in form of

Carbohydrates

Explanation:

Answer:

CHEMICAL ENERGY

Answer:

I believe it is the circulatory system.

Explanation:

Have a nice day.

Answer:

i believe it's 7

Explanation:

Answer:

a= g = - 9.81 m/s2.

The following equations will be helpful:

a = (vf - vo)/t d = vot + 1/2 at2 vf2 = vo2 + 2ad

When you substitute the specific acceleration due to gravity (g), the equations are as follows:

g = (vf - vo)/t d = vot + 1/2 gt2 vf2 = vo2 + 2gd

If the object is dropped from rest, the initial velocity ("vi") is zero. This further simplifies the equations to these:

g = vf /t d = 1/2 gt2 vf2 = 2gd

The sign convention that we will use for direction is this: "down" is the negative direction. If you are given a velocity such as -5.0 m/s, we will assume that the direction of the velocity vector is down. Also if you are told that an object falls with a velocity of 5.0 m/s, you would substitute -5.0 m/s in your equations. The sign convention would also apply to the acceleration due to gravity as shown above. The direction of the acceleration vector is down (-9.81 m/s2) because the gravitational force causing the acceleration is directed downward.

hope this info helps you out!

Answer:

It is A, B, and C

Explanation:

I just took the test!

The three characteristics mechanical waves and electromagnetic waves share are:

A. The waves begin with a disturbance.

B. The waves transfer energy from its source.

C. The waves and their energy move outward from the source.

       Usually, waves transfer energy from one place to another. Mechanical waves transfers via matter where as electromagnetic waves transfers via light. Both mechanical waves and electromagnet (light) waves measured through amplitude, wavelength, frequency and both will get transmitted, refracted, reflected, absorbed, diffracted when they react with matter. Both the electromagnetic waves and mechanical waves are transverse in nature but the mechanical waves can also be in longitudinal.

So, many characteristics were similar for mechanical waves and electromagnetic waves.

Hence, Option A, B, C are the three characteristics.

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Answer:

Average speed 62.5 miles an hour.  If the train was traveling at a constant speed in a straight line it would be much faster on getting to its destination

Explanation:

Answer:

I'm pretty sure the answer is around 9.2 seconds

Explanation:

Answer:

A. im not for sure hope it helps

Explanation:

Answer:

[tex]\huge\boxed{10\:watts}[/tex]

Explanation:

Power = Current × Voltage

P = I × V

P = 2 × 5

P = 10 watts

Answer:

Explanation:

I think this answer would be 1m to the left.