Electric power is to be generated by installing a hydraulic turbine-generator at a site 70 m below the free surface of a large water reservoir that can supply water at a rate of 1500 kg/s steadily. If the mechanical power output of the turbine is 800 kW and the electric power generation is 750 kW, determine the turbine efficiency and the combined turbine–generator efficiency of this plant. Neglect losses in the pipes.
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]
HELP ASAP !
Which of the following situations would result in no work done by the force indicated?
a
The object undergoes only a slight displacement while the force is acting on it.
b
The force is perpendicular to the displacement of the object.
c
The force is not completely parallel to the displacement of the object
d
All of the above result in no work done by the force indicated.
Answer:
b The force is perpendicular to the displacement of the object.
Explanation:
Work is done when a force is applied on a body causing it to move in a particular direction.
Work done = Force x displacement
For work to be done, a force must applied on a body to move it through a specific distance in direction.
When force is perpendicular to the displacement of the object, the component vector resolution is 0 and the work done is 0.
Which type of air mass forms over the ocean near the equator?
A
moist and warm
B
moist and cool
C
dry and warm
D
dry and cool
Answer:
a
Explanation:
Which of the following is NOT a characteristic of members of the plant kingdom?
A.Specialized tissues for water absorption
B. Cells are eukaryotic
C. Perform photosynthesis to produce glucose
D. Cell wall made of cellulose
Answer:
A. i think
Explanation:
Form hypothesis: How do you think increasing the resistance in a circuit will affect the current in the wire? (format: if, then, because)
Answer:it would make it thicker
Explanation:
Answer:
"The equation shows that the current in a circuit is inversely proportional to the resistance of the circuit. An increase in resistance would result in a decrease in current. And the factor by which the resistance increases is the same factor by which the current decreases."
Explanation:
Because it's just like wearing a glove/mitten when getting something out of the oven, because of the insulation from the glove/mitten, it reduces the heat that gets through into your hand, and it protects it. Just like what the "answer" says, it said that the resistance would decrease current.
A rat runs 2m right, turns around and runs 3m left. Then goes 2m right. What is its displacement?
A. 1m right
B. 1m left
C. 7m
D. 7m left
Answer:
Explanation:
I think this answer would be 1m to the left.
An object weighing 49 N is pushed across a floor by a force of 12 N. What is the acceleration of the object?
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
41. What effects the efficiency of a pulley?
a. the type of rope or cable
b. the way the wheel turns
c. the length of the rope
d. how big the wheel is
e. only a and be
f. all of the above
Answer:
e. only a and b
A 50 kg object is accelerating to the right at 5 m/s2. What is the net force acting on the object?
Answer:
250 NExplanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × acceleration
From the question we have
force = 50 × 5
We have the final answer as
250 NHope this helps you
7. A 1000-kg car comes to a stop without skidding. The car's brakes do 50,000 J of work
to stop the car. Which of the following was the car's velocity when the brakes were
initially applied?
Answer:
10 m/s
Explanation:
A car with a mass of 1600 kg is towing a trailer with a mass of 420 kg. The car
provides a forward thrust of 3300 N. What is the acceleration of the trailer?
Answer:
1.63366
Explanation:
I got this answer from calculator soups physics calculators. I really recommend their website for formulas.
A 20 kg mass is hanging on one side of a pulley and a 5 kg mass is hanging on the other. Determine the acceleration of each mass.
Answer:
i believe it's 7
Explanation:
Write 2 laws of reflection of light
Answer:
Answer⤵i)The first law of reflection states that the incident ray, the reflected ray, and the normal to the surface of the mirror, all lie in the same plane. ii)The second law of reflection states that the angle of reflection is equal to the angle of incidence. Both angles are measured with respect to the normal to the mirror.Which of the following is the keyboard shortcut for saving a document?
O Control V
O Control S
O Control A
O Control E
Answer:Control S, Command S on MAC=Save
A baseball on the Moon and an identical baseball on the Earth are thrown vertically upward with the same initial velocity of 12 m/s. The acceleration due to gravity on the Moon is 1/6 that of Earth. What is the maximum height the ball reaches on the moon? What is the maximum height the ball reaches on the earth? What is the difference in the maximum height the ball reaches on the Moon compared to on Earth?
Answer:
a. 3.68 m b. 0.61 m c. 3.07 m
Explanation:
a. What is the maximum height the ball reaches on the moon?
Using v² = u² - 2g'h where u = initial velocity of baseball = 12 m/s, v = final velocity of baseball = 0 m/s (since it stops at maximum height), g' = acceleration due to gravity on moon = g/6 where g = acceleration due to gravity on earth = 9.8 m/s², so g' = 9.8 m/s²/6 = 1.63 m/s² and h = maximum height of ball on moon.
So, making h subject of the formula, we have
h = -(v² - u²)/2g'
substituting the values of the variables, we have
h = -((0 m/s)² - (12 m/s)²)/2(1.63 m/s²)
= -(- 12 m²/s²)/2(1.63 m/s²)
= 6 m²/s²)/(1.63 m/s²)
= 3.68 m
b. What is the maximum height the ball reaches on the earth?
Using the same equation for the maximum height the baseball travels on the moon for that on the earth, the maximum height h' the baseball travels on the earth is given by
h' = -(v² - u²)/2g where u = initial velocity of baseball = 12 m/s, v = final velocity of baseball = 0 m/s (since it stops at maximum height), g = acceleration due to gravity on earth = 9.8 m/s²and h' = maximum height of ball on moon.
substituting the values of the variables, we have
h = -((0 m/s)² - (12 m/s)²)/2(9.8 m/s²)
= -(- 12 m²/s²)/2(9.8 m/s²)
= 6 m²/s²)/(9.8 m/s²)
= 0.61 m
c. What is the difference in the maximum height the ball reaches on the Moon compared to on Earth?
The difference in the maximum height the ball reaches on the Moon compared to on Earth is d = h - h' = 3.68 m - 0.61 m = 3.07 m
Should the resistance of an ammeter low or high ?give reason
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.
Which is true of the greenhouse effect?
A. It is purely a manmade phenomenon.
B. it does not involve carbon dioxide.
C. It causes cooling of Earth's atmosphere.
C. it traps thermal energy from the Sun.
Answer:
c is correct option thanks to brainly
where does reduction occur in an electrolytic cell
a. cathode
b. salt bridge
c. anode
d. wire
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.
What is meant by reduction ?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.
To learn more about reduction, click:
https://brainly.com/question/1222373
#SPJ2
how longitudinal waves are formed
Answer:
forever
Explanation:
A pulse with a height of 20 cm and a length of 30 cm travels with a speed of 400 cm/s through a spring that has been stretched so it is 800 cm long. If we want to send another pulse through the spring that will have a different speed, which of the bolded words should we change? List all that will change the speed of the wave.
Answer:
To send a pulse of different speed, change the tension or stretch on the spring
Explanation:
A pulse is a single disturbance of a particle is a medium. The pulse has an amplitude or and a pulse length in the medium. The speed of the pulse is dependent on the amount of strain or tension ( stretch) applied to the medium. The speed also determines the length of the pulse but is unaffected by the or amplitude of the pulse.
If a refrigerator draws about 0.5 amps when plugged into a 120 V wall outlet how much power (watts) does it use?
Answer:60 W
Explanation:
Plz di all plz i will give brainest and thanks to best answer do it right
If you add an additional neutron to an atomwhat do you create?
Answer:
However, if you add a thousand neutrons, you will be creating one super-radioactive atom. Neutrons play a major role in the mass and radioactive properties of atoms. You may have read the page on isotopes. Isotopes are created when you change the normal number of neutrons in an atom.
Explanation:
The neutron is a subatomic particle, symbol n or n⁰, which has a neutral (not positive or negative) charge and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behave similarly within the nucleus, and each has a mass of approximately one atomic mass unit, they are both referred to as nucleons. Their properties and interactions are described by nuclear physics.
21. A teacher does the following:
i. walks 4 m, south
ii. walks 8 m, east
iii. walks 4 m, north
iv. walks 8 m, west.
The overall displacement of the teacher is
a. Om
b. 6 m
c. 12 m
d. ... Nonsense! It cannot be calculated without knowing time information.
Answer:
displacement is the change from a starting point. she ends up back where she started so her displacement is zero meters although she traveled 24m in all.
How do I calculate how many meters are in 7.2 light years?
The exact question is:
Calculate in meters the distance between a galaxy and the Earth if the distance is equal to 7.2 light years.
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
Help me pretty please with a cherry on top!!
Answer:
A. im not for sure hope it helps
Explanation:
If the person's velocity is changing is the person
accelerating
Answer:
a change in velocity can be a change in magnitude (or speed), but it can also be a change in direction.
Ronald observes a large island off the coast of Indonesia on a map. A few months later, he observes that there are many smaller islands in place of the large one he had seen earlier. Which of these could have caused this change?
Answer:
idgaf
Explanation:
lol
Help please!!!
if superman at 90kg jumps a 40m building in a single bound how much work does superman perform
Answer:
5 years worth of work (aka all of the homework i currently have)
Which of the following is most accurate statement about both light and sound wave