In each cycle, a heat engine an input of 1940 J of heat and exhausts 1480 J of heat. What is the thermal efficiency?
Answer:
0.237 (23.7 %)
Explanation:
The thermal efficiency of an engine is given by:
[tex]\eta=\frac{W}{Q_{in}}[/tex]
where
W is the useful work output of the engine
[tex]Q_{in}[/tex] is the heat in input
Here we have:
[tex]Q_{in}=1940 J[/tex]
and the work done is the total heat in input minus the heat exhausted:
[tex]W=1940 J - 1480 J=460 J[/tex]
So, the efficiency is
[tex]\eta=\frac{460 J}{1940 J}=0.237[/tex] (23.7 %)
Cathy is moving into a tenth-floor apartment. She has a grand piano that weighs 570 pounds and is too big to fit in the elevator or in the stairwell.
Which simple machines would make it easiest for Cathy to get her grand piano up to her new apartment?
A.
wheels and axles
B.
inclined planes
C.
screws
D.
pulleys
She will need pulleys. Nothing else will work
The mass of an object is 201 g The object requires 150J to raise its temperature by 100°C. What is the specific heat of the object?
7.46 J/kg-K
0.00130 J/kg - K
3,020,000 J/kg . K
1500 J/kg . K
7.46J/kg-k is the correct answer
The specific heat of the object is approximately 0.746 J/g °C.
Explanation:The specific heat of an object is the amount of heat required to raise the temperature of 1 gram of the substance by 1 degree Celsius. To calculate the specific heat of the object, we can use the formula:
Specific heat = ΔQ / (mass × ΔT)
Given that the mass of the object is 201 grams and it requires 150 Joules of heat energy to raise its temperature by 100°C, we can substitute the values into the formula:
Specific heat = 150 J / (201 g × 100 °C)
Simplifying the expression, we get a specific heat of approximately 0.746 J/g °C or 7.46 J/kg-K.
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A cup falls off of a table from a height of 0.75m. What is the impact speed of the cup?
Answer:
3.822 m/s
Explanation:
You can solve this by using the kinematic equations:
[tex]v_{f} = v_{i}+gt[/tex]
[tex]d = v_it\times\dfrac{1}{2}gt^{2}[/tex]
Where:
Vf = final velocity (impact velocity)
Vi = initial velocity
g = acceleration due to gravity
d = distance traveled
t = time
Acceleration due to gravity on Earth is constant. Gravity accelerates objects towards the ground at 9.8m/s².
Initial velocity is always at 0 m/s in free fall. Let's see what we have as our given:
d = 0.75m
Vi = 0 m/s
g = 9.8 m/s²
Look at our equation for the impact velocity (Vf) with our current given plugged in:
[tex]v_{f}=v_{i}+gt[/tex]
[tex]v_{f}=0m/s+(9.8m/s^{2})(t)[/tex]
We still do not have time. That is where the second equation comes in. We plug in our values again in the secon equation and derive time:
[tex]d=v_{i}t+\dfrac{1}{2}gt^{2}\\\\0.75m=0m/s(t)+\dfrac{1}{2}(9.8m/s^{2})(t^{2})\\\\0.75m = 0+(4.9m/s^{2})(t^{2})\\\\\dfrac{0.75m}{4.9m/s^{2}}=t^{2}\\\\\sqrt{ 0.15s^{2}}=\sqrt{t^{2}}\\\\0.39s=t[/tex]
So our time is 0.39s. Now we use this in our first equation:
[tex]v_{f}=0m/s+(9.8m/s^{2})(t)[/tex]
[tex]v_{f}=(9.8m/s^{2}(0.39s)[/tex]
[tex]v_{f}=3.822m/s[/tex]
Which of the following is true about genes?
A.
Genes are made up of smaller molecules known as chromosomes.
B.
The genes of a particular organism can never change throughout its lifetime.
C.
Genes are responsible for all the traits of an organism.
D.
In humans, genes are passed to an offspring from two parents.
D. In humans, genes are passed to an offspring from two parents.
In humans, genes are passed to an offspring from two parents. Hence, option (D) is correct.
What is gene?The fundamental structural and operational component of heredity is a gene. DNA is the component of genes. Some genes serve as blueprints for the synthesis of proteins. Many genes do not, however, code for proteins. A few hundred DNA bases to more than 2 million bases make up a gene in a human.
Humans are thought to have between 20,000 and 25,000 genes, according to the Human Genome Project, an international research project that aimed to decipher the human genome's sequence and catalogue its genes.
Every gene is present in two copies, one from each parent, in every individual. Less than 1% of all genes are slightly varied between individuals, but the majority of genes are the same in all people.
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which of these describes an exothermic reaction?
1. energy is released by the reaction
2. energy is absorbed by the reaction
3. no energy is transferred by the reaction
4. energy is created in the reaction
Answer:
1
Explanation:An exothermic reaction is a reaction in which heat or light energy is released.
NEED HELP ASAP
Which of the following is a monomer of DNA?
a. Protein
b. Oil
c. Nucleotides
Answer:i think the answer is c but monomers are found in anything that has dna in it and almost everything does.
Explanation:
Answer:
C) Nucleotides
Explanation:
a train is moving at a constant speed on a surface and inclined at 10 degrees with the horizontal travels a distance of 400 m in 5 Seconds. calculate the vertical velocity component of the train during the time period.
Answer:
13.9 m/s
Explanation:
The velocity of the train along the inclined surface is given by the ratio between the distance travelled, d, and the time taken, t:
[tex]v=\frac{d}{t}[/tex]
where we have
d = 400 m
t = 5 s
Substituting,
[tex]v=\frac{400 m}{5 s}=80 m/s[/tex]
This is the velocity of the train along the inclined plane. Now we can find the vertical component of the velocity by using the formula:
[tex]v_y = v sin \theta[/tex]
where [tex]\theta=10^{\circ}[/tex] is the angle of the slope. Substituting, we find
[tex]v_y = (80 m/s)(sin 10^{\circ})=13.9 m/s[/tex]
A gasoline engine operates at a temperature of 270°C and exhausts at 210°C. Calculate the maximum efficiency of this engine. (Note that the Celsius scale is used.)
89.0 %
88.0 %
12.0 %
11.0 %
Answer:
Given:
Th = 270 °C = 270+273 = 543 K, hot temperature
Tc = 210 °C = 210+273 = 363 K, cold temperature
According to the Carnot theorem, the maximum efficiency achievable by a heat engine between a hot and cold temperature is
η = 1 - Tc/Th
= 1 - 363/543
= 0.668 = 11.047 (approx)
Answer: 11.0% (nearest integer)
Answer:
Hello! the efficiency of a thermal engine depends on how much of the initial input is transformed into work, Here 270°c is the input and 210°c is the output.
Then the efficiency is calculated as e = 1 - Tc/Th, where Th is the hot temperature (in this case 270°C) and Tc is the cold temperature (in this case 210°C)
First we need to write the temperatures in kelvin degrees, this can be done by adding 273.15 to the celsius scale:
Th = 270 + 273.15 = 543.15
Tc = 210 +273.15 = 483.15
then the efficiency is e = 1 - 543.15/483.15 = 0.11
if we write this as a percentage, we get an efficiency of 11%, then the fourth answer is the correct one.
In order to boil an egg, a student puts the egg in a pan of water and heats the pan on the stove. Which methods of the heat transfer are used to transfer the majority of the heat to the water and the egg?
Answer:
Convection (heat transfer from boiling water)
Conduction (heat transfer from the bottom the of pan)
Explanation:
Convection is heat flux through liquids and gases.
Conduction is heat flux through solid materials.
Radiation is heat flux through electromagnetic waves.
Suzie stands on a pedestal and touches the dome of a running Van de Graaf generator. In a few seconds she observes her hair standing on end. Explain this observation.
A)
Each hair was induced with a positive charge. Each hair repels against its neighbor and stands up.
B)
Each hair was induced with a positive charge. Each hair is attracted to its neighbor and stands up.
C)
Half of Suzie's hairs were charged negative, and the other half charged positive. The different charged hairs repel each other and stand up.
D)
Half of Suzie's hairs were charged negative, and the other half charged positive. The different charged hairs attract to each other and stand up.
Answer:A
Explanation:
Answer:
A)
Each hair was induced with a positive charge. Each hair repels against its neighbor and stands up.
Explanation:
When we touch the Van-de-Graff generator then due to high potential of the generator the charge is induced in our hairs.
Due to induction of charge in hairs all the hairs get similar charge and this similar charge is on each hair is along its whole length.
Now due to coulombs law all hairs are repelling each other due to similar nature of charge and this repulsion against each neighboring hair will stand the hairs upwards
so correct answer will be
A)
Each hair was induced with a positive charge. Each hair repels against its neighbor and stands up.
A turntable with a radius of 8cm rotates at 45 rpm. What is the linear speed of a point on the outside rim?
The linear speed of a point on the rim of a turntable rotating at 45 rpm with a radius of 8 cm is calculated by initially converting the rpm to radians per second, and then using the formula for linear speed. The resulting linear speed is 0.36 π m/s, which is about 1.13 m/s.
To calculate the linear speed of a point on the rim of a turntable rotating at 45 rpm with a radius of 8 cm, we need to use the relationship between angular velocity (in radians per second) and linear speed. First, we convert the rotation rate from rotations per minute (rpm) to radians per second. Since there are 2π radians in one rotation and 60 seconds in one minute, the conversion factor is 2π/60 radian/minute.
So, the angular velocity ω is:
ω = 45 rpm × (2π/60 rad/min) = 4.5 × π rad/s
Then, we use the formula for linear speed v which is:
v = rω
where r is the radius in meters (0.08 m for 8 cm), ω is the angular velocity in radians per second. Plugging in the values we get:
v = 0.08 m × (4.5 × π rad/s) = 0.36 × π m/s
Thus, the linear speed of a point on the outside rim of the turntable is 0.36 × π m/s, which is approximately 1.13 m/s.
Why are some scientists skeptical of the scientists results and conclusions
Earth's surface temperature has warmed 1.5 degrees Celsius over the past 250 years and "humans are almost entirely the cause," concludes a scientific study designed to address skeptical concerns that the causes of climate change are even induced. for the man. Professor Richard Muller, a climate change physicist and founder of the Berkeley Earth Surface Temperature Project, said he was surprised by the findings. "We did not expect this result, but as scientists it is our duty to let the evidence change our minds." He added that he now considers himself a "converted skeptic" and his views have been subjected to a "total turnaround" in a short time. "Our results show that the average land surface temperature has increased by 1.5 degrees Celsius over the last 250 years, including an increase of 0.9 degrees Celsius over the last 50 years. In addition, it seems likely that essentially all of this increase results from human emissions of greenhouse gases, ”Muller wrote in an article in the New York Times. The University of California, Berkeley-based team of scientists has assembled and consolidated a set of 14.4 million surface temperature observations, collected from 44,455 sites worldwide, dating back to 1753. Previous datasets created by NASA and the National Oceanic and Atmospheric Administration (NOAA) in the US, and by the Met Office and the Department of Climate Research at the University of East Anglia in the United Kingdom only arrived until the mid-19th century and used only a fifth of the number. of weather station records
A timline is necessary :
A.for every goal
B.for every academic goal
C.for every life goal
D.for every high school goal
Answer:
A. For every goal
Explanation:
A timeline is necessary for every goal set, be it academic, life, high school, personal, and the like. A timeline is an important part of goal setting. It helps determine what should be done by a certain time to ensure that you will reach your goal. Although some goals can take a long time to reach, a timeline will be your constant reminder of what needs to be done.
When setting a timeline, you also need to take in consideration what you want to achieve. You need to set a realistic timeline as many usually underestimate the obstacles they may face in pursuing their goals.
Oil is a natural resource that is found inside of earth. Oil can be used
A) to grow plants.
B) to cook dinner.
C) to fuel vehicles.
D) to construct houses.
Is C the correct answer.
Yes c is correct good job
Oil is a natural source that can be used to cook food items and fuel vehicles. There are different kinds of oils classified based on the source from there it is extracted.
What is oil ?Any nonpolar chemical compound that is mostly hydrocarbon-based, hydrophobic and lipophilic is considered to be an oil . Typically combustible and surface active, oils. Most oils are lipids that are liquid at room temperature and are unsaturated.
Classes of chemical substances that may be otherwise unrelated in structure, characteristics, and usage are included in the generic concept of oil. Oils can have a volatile or non-volatile composition and come from either plant, animal, or petrochemical sources.
They are used in food (such as olive oil), fuel, medicine (such as mineral oil), lubrication (such as motor oil), and the production of several paint and plastic products, among other things. Some religious rites and rituals employ specially formulated oils as cleansing elements.
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A 2600 kilogram car is moving at a speed of 25m/s. How much kinetic energy does the car have
The kinetic energy of a 2600-kilogram car moving at a speed of 25 meters per second is 812,500 Joules.
Explanation:The kinetic energy of an object can be calculated using the formula: Kinetic Energy (KE) = 0.5 * mass * velocity2. In this case, the mass of the car is 2600 kilograms and the velocity is 25 m/s. Plugging these values into the formula, we get KE = 0.5 * 2600 kg * (25 m/s)2 = 812500 Joules. Therefore, the car's kinetic energy at that speed would be 812,500 Joules.
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what is albert einsteins contribution to the understanding of nucear energy?
Answer:
He was able to prove that matter and energy are inter-convertible, and mass may be used to measure the total energy present in an object.
Explanation:
He observed a mass defect in nuclear reaction products and the reactants. Thus, mass may be used to measure the total energy present in an object by the use of the equation;
E = m × [tex]c^{2}[/tex]
Where: E is the energy, m is the mass and c is the constant speed of light.
He developed the use of nuclear reactions to generate heat energy, which has a great applications in atomic bombs.
IDENTIFY and DESCRIBE the six climate regions.
Answer:
6 climate regions are Mediterranean, Polar, Tropical, Temperate, Arid and Tundra.
Explanation:
There are six main climate regions in the world. These regions distinguished from one another on the basis of climate that exists there. Above mentioned climates are described shortly as follows:
Mediterranean: This region is the region surrounding the Mediterranean sea, Southern California and Southern America. The climate in this region is hot and dry in summer whereas mild winters are there in this region.
Polar: This region is on the South Pole, near the side of Greenland. The climate in this region is very cold and chilled.
Tropical: This region consists of jungles of South America, Africa, some parts of Asia and the islands of Pacific. The climate of this region is Hot. Due to heavy rainfalls in this area, the area is also wet.
Temperate: North America, Europe and Northern Asia is included in this region. The climate is mild hot in summers and cold in winters.
Arid: This region consists of deserts of Africa, Asia, US and Australia. The climate is very hot throughout the year.
Tundra: This region consists of the mountain tops of America, Asia and Greenland. The climate is extremely cold in such regions throughout the year.
Taphonomy is the study of what happens to animals or humans between the time that they die and the time that their remains are found.
Answer:
True.
Explanation:
The formation of fossils is associated with a series of biological and geological events beginning with the death of an organism. This is followed by a series of events, such as necrolysis, disarticulation, transport and burial of the remains, until the final occurrence of the physicochemical processes that transform sediments into rock and fossilize the organisms deposited therein. The area of paleontology that deals with unraveling all the processes mentioned above is taphonomy. With that we can say yes, Taphonomy is the study of what happens to animals or humans between the time they die and the time their remains are found.
Naoki's bicycle has a mass of 11 kg. If Naoki sits on her bicycle and starts pedaling with a force of 110.5 N, causing an acceleration of 1.7 m/s2, what is Naoki's mass?
Naoki's mass is calculated to be 54 kg by using Newton's second law of motion and subtracting the bicycle's mass from the total mass obtained when the force and acceleration are considered.
To determine Naoki's mass given that her bicycle has a mass of 11 kg and she accelerates it with a force of 110.5 N at an acceleration of 1.7 m/s², we can use Newton's second law of motion, which states that force equals mass times acceleration (F = m * a). Here, the total mass includes both Naoki's mass and the bicycle's mass.
First, we calculate the total mass by rearranging the equation to m = F / a. Substituting in the known values, we get m = 110.5 N / 1.7 m/s², which gives us a total mass of 65 kg. Since we know the bicycle's mass is 11 kg, we subtract this from the total mass to find Naoki's mass: 65 kg - 11 kg = 54 kg. Therefore, Naoki's mass is 54 kg.
What is the wavelength of a wave if the wave speed is 24 m/s and the frequency is 48 Hz?
Answer:
Wavelength is 0.5
Explanation:
To work it out, you divide Wave speed by the Frequency (24÷48=0.5)
Answer:
wavelength = 0.5 meters
Explanation:
Wavelength is the distance between successive trough or crest of a wave. Wavelength is inversely proportional to frequency. This means the shorter the wavelength the higher the frequency .The S.I unit of wavelength is meters.
Wavelength can be represented with a Greek symbol known as lambda (λ).
The formula below can be use to represent wavelength .
λ = v/f
where λ = wavelength
v = velocity
f = frequency
v = 24m/s
f = 48 Hertz
λ = 24/48
λ = 0.5meters
Which image depicts projectile motion?
Answer:
the answer is the second one
Explanation:
the person is moving through the air while the other people are either not moving forward or backwards or on the ground with full controll over where they go
Answer:
Second picture is representing projectile motion
Explanation:
As we know that in projectile motion one of the component of the motion of object will remains constant while other component which is vertical in direction will change due to gravity.
So here in this type of motion the path of the object is same as the parabolic path.
Here we know that vertical component of the motion will change due to gravity while horizontal component will remain constant always
So here we can say that
correct image is second image
Which property of sound waves decreases as the square of the distance from the source increases?
Intensity is the answer
Answer:
Intensity
Explanation:
The intensity of a sound wave is equal to the ratio between to the power emitted by the source divided by the area of the spherical surface through which the wave propagates:
[tex]I=\frac{P}{4\pi r^2}[/tex]
where
P is the power
[tex]4\pi r^2[/tex] is the area of the spherical surface
r is the distance from the source
As we see from the formula, the intensity is inversely proportional to the square of the distance from the source:
[tex]I\propto \frac{1}{r^2}[/tex]
so, intensity is the correct answer.
Answer:
The answer is intensity.
Explanation:
I took AP EX quiz.
what is the SI unit of force?
The SI unit of force is the Newton .
1 Newton is the force that accelerates 1 kilogram of mass at the rate of 1 meter per second-squared.
1 pound of force is roughly 4.45 Newtons of force.
So 1 Newton of force is roughly 3.6 ounces of force.
1 kilogram of mass weighs about 9.81 Newtons on Earth. That's the same as 2.205 pounds.
Answer
the SI unit of force is newton
When forces are balanced, what affect does that have on the motion of an object?
Balanced forces cause no change in motion, even if the object is moving.
According to Newton’s 1st law, all objects remain stable unless acted upon by an unbalanced force, so this means that since the forces are balanced, the motion would remain at rest. If there was a greater force on one side of the object, then it would be pushed to the other side (ex. Pushing a heavy box from the right, makes it go left). I hope that helps...
Infrared light has a longer wavelength than WHAT? but a shorter wavelength than WHAT?
Infrared light has longer wavelengths than gamma rays, X-rays, ultraviolet light, and visible light, but shorter wavelengths than microwaves, radar, GPS, cellphone, TV, radio, ocean, audible sound, ultrasound, seismic, guitar-string, and Slinky™ waves.
The requried, Infrared light has a longer wavelength than visible light, but a shorter wavelength than radio waves.
What is wavelength?Wavelength is a fundamental property of waves, including electromagnetic waves like light and radio waves, as well as other types of waves, such as sound waves or water waves.
Visible light has wavelengths ranging from approximately 400 to 700 nanometers, while infrared light has longer wavelengths ranging from about 700 nanometers to 1 millimeter. Radio waves, on the other hand, have even longer wavelengths than infrared, ranging from a few millimeters to several meters or more.
It's worth noting that the distinction between different types of electromagnetic radiation, including infrared, visible light, and radio waves, is based on their wavelengths and frequencies. However, these distinctions are not always clear-cut, as there can be some overlap in the wavelengths or frequencies of adjacent types of radiation.
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What type of image can a convex mirror produce?
A. a real image
B. a refracted image
C. a virtual image
It must be a virtual image, because this is the only kind of image it can produce.
Please help
Need to put these according to the selected sections
picture 1 is choices
where to put those choices:
Conduction
Convection
Radiation
Answer:
conduction
burning yourself by touching boiling water
grabbing a warm coffee mug to warm your hands
the handle of a pot becoming too hot to grab as it cooks on the stove
convection
warm water rising to the surface of the ocean and cooler water sinking
radiation
cooking popcorn using a microwave
Explanation:
Answer:
Answer:
conduction
burning yourself by touching boiling water
grabbing a warm coffee mug to warm your hands
the handle of a pot becoming too hot to grab as it cooks on the stove
convection
warm water rising to the surface of the ocean and cooler water sinking
radiation
cooking popcorn using a microwave
Explanation:
When you do work on something, you give it energy
Select the correct answer from each drop-down menu.
Brass and bronze are both A.___ of copper because copper is the B.___ component in brass and bronze.
A.
alloys
composites
variations
void
B.
main
most dense
most expensive
only
Answer:
A. ) alloys
B. ) main
Explanation:
Brass and bronze are both alloys(A) of copper because copper is the main(B) component in brass and bronze.
Explanation:
Brass and Bronze are used in our day to day life known as metal alloys. Brass is an alloy of the metals like copper and zinc which has high percentage of metal copper with tin combined with it.
Brass is dull yellow in color. Bronze is reddish brown in color. Brass was known to be present in 500 BC. Bronze was about 3500 BC known to be present. Thus Bronze and Brass are both alloys of the metal copper since the main component in the brass and bronze is copper.