Answer:
(a) η = 0.1742 = 17.42 %
(b) W = 31.64 W
(c) m = 0.58 kg
Explanation:
(a)
The efficiency of a Carnot's engine is given as follows:
[tex]\eta = 1-\frac{T_2}{T_1}[/tex]
where,
η = efficiency = ?
T₁ = source temperature = 100°C + 273 = 373 K
T₂ = sink temperature = 35°C + 273 = 308 K
Therefore,
[tex]\eta = 1 - \frac{308\ k}{373\ k} \\[/tex]
η = 0.1742 = 17.42 %
(b)
Another formula for the efficiency of Carnot's Engine is:
[tex]\eta = 1 - \frac{Q_2}{Q_1}[/tex]
where,
Q₁ = Input heat rate
Q₂ = Heat rejected = 150 W
Therefore,
[tex]0.1742 = 1 - \frac{150\ W}{Q_1}\\\\ \frac{150\ W}{Q_1} = 1-0.1742\\\\Q_1 = \frac{150\ W}{0.8258}[/tex]
Q₁ = 181.64 W
Now, for the useful power output:
[tex]W = Q_1-Q_2\\W = 181.64\ W - 150\ W\\W = 31.64\ W[/tex]
where,
W = Useful Output
W = 31.64 W
(c)
The heat required to condense steam i given as:
[tex]Q = mH\\Q_1t=mH\\m = \frac{Q_1t}{H}[/tex]
where,
m = mass of steam condensed = ?
t = time = 2 h = 7200 s
H = Latent heat of condensation of steam = 2260 KJ/kg = 2260000 J/kg
Therefore,
[tex]m = \frac{(181.64\ W)(7200\ s)}{(2260000\ J/kg)}[/tex]
m = 0.58 kg
A man is driving his 1100 kg car at 36 km/h on a straight freeway. After accelerating for 30 seconds, the car
has a speed of 108 km/h. How much work did the engine do during the 30 seconds?
Answer:
W = 439998 J = 439.99 KJ
Explanation:
First, we will calculate the acceleration of the car by using the first equation of motion:
[tex]v_f = v_i + at\\\\a = \frac{v_f-v_i}{t}[/tex]
where,
a = acceleration = ?
vf = final speed = [tex]108(\frac{km}{h})(\frac{1000\ m}{1\ km})(\frac{1\ h}{3600\ s})[/tex] = 30 m/s
vi = initial speed = [tex]36(\frac{km}{h})(\frac{1000\ m}{1\ km})(\frac{1\ h}{3600\ s})[/tex] = 10 m/s
t = time = 30 s
Therefore,
[tex]a = \frac{30\ m/s - 10\ m/s}{30\ s}[/tex]
a = 0.67 m/s²
Now, we will calculate the force applied by the engine:
F = ma
where,
F = force = ?
m = mass = 1100 kg
Therefore,
F = (1100 kg)(0.67 m/s²)
F = 733.3 N
Now, we will calculate the distance covered by the car by using the second equation of motion:
[tex]s = v_it+\frac{1}{2}at^2\\\\s = (10\ m/s)(30\ s)+\frac{1}{2} (0.67\ m/s^2)(30\ s)^2[/tex]
s = 600 m
Now, the work done (W) by engine can be calculated as follows:
W = Fs
W = (733.3 N)(600 m)
W = 439998 J = 439.99 KJ
If there is a negative sign in front of the Hooke's Law equation, what does the force, F, represent?
Answer:
Hooke's law, given by [tex]F=-kx[/tex] is denoted with a negative sign to regard that the direction of restoring force that occurs opposite in direction of the force that caused the displacement [tex]x[/tex]. F represents the force required to create a spring displacement of [tex]x[/tex].
Explanation:
As with many things in physics, the negative sign represents direction. In this case, after a spring is displaced a distance of [tex]x[/tex] from equilibrium, the restoring force created by the spring will be in opposite direction of the force applied to move the spring there, represented by F.
on which factor does gravitation between any two bodies depend?
Answer:
Gravitational force between two bodies depends on:
1. Masses of the two bodies. The greater an object's mass, the greater its gravitational force.
2. Distance of separation between them. The smaller the distance greater is the gravitational force.
14 What is the weight of each of
the following masses on Eth?
a) 2 kg
b) 3.5kg
c) 5.25 kg
Newton’s
Explanation:
On earth,
g=10 m/s^2
When M=2 kg,
weight on earth=2×10
=20N
When M=3.5 kg,
weight on Earth=3.5×10
=35N
When M=5kg,
weight on Earth=5.25×10
=52.5N
please help me asap thankss
EXPLAIN WHY A POLYTHENE ROD GAINS A NEGATIVE CHARGE WHEN IT IS RUBBED WITH A CLOTH
Answer:
When a polythene rod is rubbed with a duster, the friction causes electrons to gain energy. Electrons gain enough energy to leave the atom and 'rub off' onto the polythene rod. The polythene rod has gained electrons, giving it a negative charge.
Explanation:
Hope it helps
What helps night vision? Answer fast please.
Answer:
Halos, blurriness, and night blindness causes night vision (symptoms) while vitamin-A,corrective lenses, such as eyeglasses or contacts, can improve or help night vision.
Explanation:
I bet you will get full Marks if you write it!!
(please note that you will have to mark me as brainliest if it helped you)£
After going through the hoop, a basketball falls to the floor 3 meters below the hoop. The ball
has a kinetic energy of 17.6 Joules as it strikes the ground. What is the potential energy at the hoop?
Answer:
immma send you the link friend me on hereExplanation:
hello help me please :)
Answer: 75 N
Because we're finding the force, we need to use F = ma. M (Mass) = 25 and A (Acceleration) = 3. Multiply 25(3) to get 75. So, you're answer should be 75 N.
The density of silver is 10.49 g/cm3. If a sample of pure silver has a volume of 12.993 cm3, what is the mass?
Explanation:
Density=mass/volume
mass=x
10.49=X/12.99
X=10.49 X12.99
X=136.29657
mass=136.3g/cm^3
I hope it helped.
What is the wavelength of sound wave in air that has a temperature of 24.6°C that has a frequency of 440.8 Hz?
A. 465.40 m
B. 0.78 m
C. 17.92 m
D. 0.75 m
Does a battery produce electric currents?
Answer:
A battery is a device that stores chemical energy and converts it to electrical energy. The chemical reactions in a battery involve the flow of electrons from one material (electrode) to another, through an external circuit. The flow of electrons provides an electric current that can be used to do work.
You have your headphones turned all the way up (100 dB).
a. If you want them to sound half as loud, to what decibel level must the music be set?
b. If you want them to sound 1/4 as loud, to what decibel level must the music be set?
Answer:
a. 90 dB
b. 80 dB
Explanation:
The given parameter of the sound is as follows;
The level to which the headphones are tuned = All the way up
The intensity of the sound of the headphones when tuned all the way up = 100 dB
a. The relationship between level change in loudness, ΔL, and the ratio of loudness, 'x', is presented as follows;
ΔL = 10·log₂(x) ≈ 33.22·log(x)
Therefore, for a sound to be half as loud, we have x = 1/2, therefore;
ΔL = 10·log₂(1/2) = 10·log₂(2⁻¹) = -10 ≈ 33.22·log(1/2)
The change in the intensity level for a sound half as loud, ΔL = -10 dB
Given that the sound was initially at 100 dB, the new level for a sound half as loud = 100 dB + ΔL = 100 dB - 10 dB = 90 dB
The decibel level the music must be set for a sound half as loud = 90 dB
b. In order for the sound to be 1/4 as loud, we have;
ΔL = 10·log₂(1/4) = 10·log₂(2⁻²) = -20
Therefore, the change in the level of the sound intensity level, ΔL by -20 dB will given a sound that is 1/4 as loud
The initial intensity level = 100 dB
The intensity level for a sound 1/4 as loud = 100 dB - 20 dB = 80 dB
A ball sits on the table not moving. A child comes along and gives the ball a push. Which law is best described by this example?
A. Newton's First Law
B. Newton's Second Law
C. Newton's Third Law
D. Avagadro's Law
Answer:
A Newton's First law
Explanation:
In Newtons first law of motion it states that that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. Which mean the ball will not move until the force of the child come and pushes on the ball.
At the end of 3N force acts on the object during time interval of 1.5seconds with force acting towards right. A constant force of 4N to left is applied for 3seconds. What is the velocity at the end of the 3seconds ?
Answer:
v_f = -7.5 m / s
Explanation:
Let's analyze this exercise a little, two forces that act on a body for different time intervals are indicated, each force creates an impulse and since this is a vector quantity we must add in the form of vectors. The net momentum is
we assume that the direction to the right is positive
I = I₁ + I₂
I = F₁ Δt₁ - F₂ Δt₂
I = 3 1.5 - 4 3
I = -7.5 N s
now let's use the relationship between momentum and momentum, suppose the object starts from rest (vo = 0)
I = Δp
I = m (v_f - v₀)
v_f = I / m
v_f = -7.5 / m
to finish the calculation we must assume a mass m = 1 kg
v_f = -7.5 m / s
the negative sign in the body is moving to the left
which instrument determine the purity of milk
Answer:
Milk Lactometer
Milk Lactometer: A lactometer is an instrument that is used to check for the purity of milk by measuring its density.
lactometer is used to determine the purity of milk
hope it is helpful to you
How much gravitational potential energy has a boy whose mass is 50 kg and
who is standing on top of a 2.5 meter high wall?
a. none of these
b. 0735 j
c. 2115 j
d. 196
Answer:
Gravitational potential=mgh
=50×10×2.5
=1250J
option a
What is the function of Soda Line
A planet orbits a sun in a clockwise elliptical orbit as shown in the diagram below
Bubble in the letter representing the position or choose e if it is constant
At which position does the planet have the greatest gravitational energy?
Answer:
Greatest gravitational energy is at "C".
The planet has to do work "against" the field to get to "C".
Also, if m v R (angular momentum) is constant then as R increases v must decrease for this term to be constant and KE = 1/2 M v^2 must decrease also to get to point C.
which feature is used to classify galaxies
age
color
shape
size
Answer:Shape
I took the quiz
Answer:shape
Explanation:
I took the quiz
A gold pendulum swings with angular acceleration a, and a point on the edge has tangential acceleration a. A silver pendulum swings with angular acceleration 3a, and a point on the edge has tangential acceleration 5a. How does the radius of the gold pendulum r gold compare with the silver pendulum r silver ?
A 1/15
B 5/3
C 15
D 3/5
Answer:
D - 3/5r
Explanation:
Khan Academy
Genes consist of portions of ______.
~Chapter Name: Heats and its effects ~
(Collecting Information)
how does a veterinary doctor (a doctor who treats animals) find out the body temperature of domestic animals or birds?
Go to the nearest veterinary clinic and find out
(I don't have a clinic near it miles away so pls help)
Answer:
Either orally or rectally
Explanation:
(I didn't visit the vet clinic, I just searched it up)
It depends on the animal. You can't check a birds temperature with a thermometer because it will rupture its cloaca gland but you can check its poop.
Answer:
thermometer is used by veterinary doctors to find out the temperature of domestic animals .
True or False?
________________The fact that ocean crust is younger the farther away it is from an ocean ridge supports the theory of plate tectonics
Answer:
true is the answer of the question
A worker leaves home at 9:00 AM, travels 40 km to the office, and then returns home at 5:00 PM. What is the magnitude of the worker's displacement during this 8-hour span of time?
Answer:
The answer is 0km
Explanation:
The game of floor hockey is primarily a blank
and blank
game.
Answer:
Fast and Energetic
Explanation:
The game of floor hockey is primarily a Fast and Energetic game. The main objective of the game of field hockey is to score more goals than the opposing team by shooting the Hockey ball into the goal post of the opposing team, Field hockey is similar to Ice hockey but the major difference is that Filed hockey is played without skates
Question 1 (1 point)
All solid objects will deform when enough force is applied.
O True
False
Answer:
Solid objects will deform when adequate loads are applied to them; if the material is elastic, the object will return to its initial shape and size after removal. This is in contrast to plasticity, in which the object fails to do so and instead remains in its deformed state.
Explanation:
Answer:
It is false
Explanation:
because when it like a rolling ball it can deform no matter what unlesss you throw it at the ground really hard then it breaks but a soft or sometimes metal yeah it can deform but not all things solid deform.
Which activities will help improve your flexibility? A. Yoga B. Dance C. Pilates D. All of the above
Answer: I believe that the answer is D.
Explanation:
Hope this helps and have a great day! :)
Answer:
D) all of the above
Explanation:
How could nanotechnology best be used to improve the treatment of cancer with chemotherapy?
A. A nanometer-size carrier could be designed to bring the chemotherapy drugs only to cancer cells.
B. A nano carbon wire could be designed that would aid in the manufacture of chemotherapy drugs.
C. A quantum dot could be used to watch where the chemotherapy drugs go in the body.
D. Biomaterials could be made that would allow for cell growth within the cancer cells so that they are easier to find.
Answer: A
Explanation: Edg2020
Elena puts her eggs in a cage made out of wood. The wood breaks during
the landing, but the eggs survive. Which would be the best reason to
explain why this prevented her eggs from breaking?"
O Directs the energy of the impact towards the egg
O Decreases the velocity of the egg before it starts slowing down
O Increases the time that the egg slows down
O Decreases the time that the egg slows down.
O Directs the energy of the impact away from the egg
O Increases the velocity of the egg before it starts slowing down
Answer:
I think the answer is Decreases the time that the egg slows down.
Explanation:
If not try it starts slowing down
O Increases the time that the egg slows down.
how is an earthquake's origin and intensity identified?
Answer:
using a seismograph
Explanation: