Answer:
a. 30%
Explanation:
Given the following data;
Energy as effort, Ee = 20 J
Energy as heat, Eh = 6 J
To find the percentage efficiency (P.E);
P.E = Eh/Ee * 100
Substituting into the formula, we have;
P.E = 6/20 * 100
P.E = 6 * 5
P.E = 30 %
Therefore, the percentage efficiency of the machine is 30 %.
The three things to remember about gravitational forces in space are: 1. 2. 3.
Answer:
(1) The gravitational forces are inversely proportional to the square of the distance between the objects. More is the distance between the objects , less will be the gravitational force between them.
(2) The gravitational forces are the weakest of all the four fundamental forces (Nuclear forces, weak forces, electromagnetic forces, gravitational forces) in nature.
(3)Gravitational forces are always attractive . They are also conservative in nature. work done by these forces or against these forces doesn't depend on the path followed.
Explanation:
Calculate the pressure exerted on the floor by the boy standing on both feet if the weight of the boy is 40kg. Assume that the area of each of his shoes is 6cm x 25cm.
(Take 1kg of weight = 10N)
Answer:
P = 1333.33 N
Explanation:
The pressure exerted by the boy on the floor can be calculated by the following equation:
[tex]P = \frac{F}{A}[/tex]
where,
P = Pressure exerted by the boy = ?
F = Force Applied = Weight of Boy = 40 kg = 40 N (since 1 kg = 1N)
A = Area of application of force = 2(Area of one show) = 2(6 cm x 25 cm)
A = 2(0.06 m x 0.25 m) = 0.03 m²
Therefore,
[tex]P = \frac{40\ N}{0.03\ m^2}\\\\[/tex]
P = 1333.33 N
One way to think about circular motion is that the object is continuously ____________.
A. Prevented from moving in a straight line.
B. Allowed to move in a straight line.
C. Forced to move in a straight line.
D. Encouraged to move in a straight line.
Answer:
A
Explanation:
circular motion means the object will follow a circular trajectory.
Answer:
the answer for the question is option A
7. A train 100 m long is moving with the velocity of 72 km/h. Find the time it takes to cross the bridge which is 2 km long?
a) 1050 S
b) 10500 s
c) 10.5 s
d) 105 s
Answer:
d) 105 s
Explanation:
Given the following data;
Distance A (length of train) = 100 m
Velocity = 72 km/h to meters per seconds = 72 * 1000)/3600 = 72000/3600 = 20 m/s
To find the time;
Time = distance/speed
Time = 100/20
Time = 5 seconds.
II. When the distance (bridge) is 2km;
Distance B = 2km = 2*1000 = 2000 meters
Time = distance/speed
Time = 2000/20
Time = 100 seconds
Therefore, total time = 5 + 100 = 105 seconds
In a perfectly inelastic collision between two balls:
a) No changes happen to the internal structure of the balls
b) The total kinetic energy of the balls is conserved
c) The balls have the same velocity after the collision
d) The balls temperature does not change.
Answer:
c) The balls have the same velocity after the collision
Explanation:
In a perfectly inelastic collision between two balls, there is a loss in the maximum kinetic energy of the system and the two ball stick together, and thereby have the same velocity after the collision and also the coefficient of restitution of the two balls is also zero accompanied by a loss in the kinetic energy of the system
Therefore, the correct option is that both balls will have the same (equal) velocity after the collision.
Which is NOT something that all green plants have in common?
1.They make their own food.
2. They reproduce.
3 .They grow.
4 .They produce flowers.
Answer:
4
Explanation:
Not all plants can grow flowers. Only the ones thay have buds can.
Not all plants produce flowers. Hence, this is the characteristic which is not common in all plants.Therefore, the correct option is 4.
What are flowers?Flowers are the structures of plants. They are responsible for producing seeds that will grow into new plants. Flowers typically consist of a colorful or ornamental part called the corolla, which attracts pollinators such as bees and butterflies, and a reproductive part called the stamen and pistil, which contain the plant's male and female organs.
Not all green plants produce flowers. Flowering plants are a type of plant that belong to the group Angiosperms, but there are also non-flowering plants like ferns and mosses that do not produce flowers. Therefore, the correct option is 4.
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Question- Gases the oceans exchange with the atmosphere include..
a. oxygen
b. carbon dioxide
c. water vapor
d. all of the above
PLEASE HELP ME
Which refers to the amount of energy in a sound wave per unit of time and is also related to the loudness of a sound? period compression amplitude intensity
Answer: Thanks for the points!
Explanation: The average amount of energy passing through a unit area per unit of time in a specified direction is called the intensity of the wave. As the amplitude of the sound wave increases, the intensity of the sound increases. Sounds with higher intensities are perceived to be louder.
Answer:
Amplitude
Explanation:
What are the four major tasks of the digestive system?
Ingestion, Digestion, Absorption, Elimination.
Ingestion, Procrastination, Absorption, Face the Nation.
Congestion, Progestion, Ingestion, Elimination
Answer:
Option A
The four major tasks of the digestive system are - Ingestion, Digestion, Absorption, Elimination
Explanation:
A digestive system has primarily four main functions
a) Motility - In this the food is ingested through opening in the form of mouth and then it starts moving from the mouth via esophagus to the stomach
b) Digestion - In the stomach, the food gets digestion and then it is passed on to the intestine
c) Absorption - In the small intestine essential nutrients and water is absorbed
b) Secretion - The waste remaining after intestine digestion is passed on to the rectum for secretion
Hence, option A is correct
nt: what is the unit of measurement for work?)
A body builder lifts a 200kg barbell up 2m into the air. How
much work does the bodybuilder do?
Answer:
The unit of measurement of work is Nm which is also called as Joule and written J.
work done by the body builder against gravity = 3920J
Explanation:
work = force x displacement
force on barrel = 200 x gravity = 200 x 9.8 = 1960 N
displacement = 2m
work done against gravity = 1960 x 2 = 3920 J
A 1200 kg car accelerats from reat to 10.0 m/s in a time of 4.50 seconds. Calculate the force that thr car's tires exerted on the road.
Answer:
2667 N
Explanation:
Method 1: ImpulseWe can solve this problem by using the impulse formula.
FΔt = mΔv Δt = time interval, m = mass of the car (kg), Δv = change in velocityWe have three known variables, so we can solve for the fourth: F.
Divide Δt from both sides to isolate F.
F = (mΔv)/ΔtSubstitute known values into the equation.
F = [(1200 kg)(10 m/s - 0 m/s)] / 4.5 s F = [(1200)(10)]/4.5 F = 12000/4.5 F = 2666.666667 NThe force that the car's tires exert on the road is 2667 N.
Method 2: Newton's Second LawThe force that the car's tires exert on the road is equivalent to the force that the road exerts on the car due to Newton's Third Law of Motion.
We can calculate the force that the car's tires exert on the road by using the formula F = ma, which was derived from Newton's Second Law of Motion.
F = ma F = force exerted on the car, m = mass of the car (kg), a = acceleration of the car (m/s²)We are given the mass of the car, velocity of the car, and the time in which it accelerated.
We can use this equation for acceleration:
a = Δv/Δt Δv = final velocity - initial velocity (change in velocity), Δt = time intervalThe car started from rest, meaning it had an initial velocity of 0 m/s. Its final velocity was 10 m/s. The time that it took for the car to go from 0 m/s to 10 m/s was 4.5 seconds.
a = (10 m/s - 0 m/s) / 4.50 s a = 10/4.5 a = 2.222... m/s²Now we have two known variables, mass and acceleration. We can solve for the force exerted on the car (and thus, the force the car exerts on the road) using the formula F = ma.
F = ma F = (1200 kg)(2.222... m/s²) F = 1200 · 2.222...F = 2666.666667 NThe force that the car's tires exert on the road is 2667 N.
This Is Science , please help it’s due at 3 , but I dont mind if its a little late.
Answer:
uhm you can get all these answers from go ogle but just so you dot get in trouble click the tree dots at the top right of your screen (this is if your using crome) and go to history click the square and there should be a delete thing
Explanation:
Answer:
4. I and II 9. tornado
Explanation:
a student had rolled 114 dice and removed all those landed on the number six. the student rolled the remaining dice again and removed those that landed on a six. when the student had rolled the dice 20 times there were 9 dice left.
Calculate the most likely number of times that the student had rolled the dice before the number of dice had halved.
Answer:
4 rolls
Explanation:
The probability of rolling a 6 is 1/6 = 0.1667 (4.d.p)
This means that approx. 1/6 of the dice will land on a 6.
If the student removes a 1/6 of the dice each time, it means that the number of dice is decreasing by 1/6 each roll (or multiplying by 5/6).
114/2 = 57
By multiplying 114 by 5/6 and continuing we can see how many times it takes for us to get past 57.
Roll 1: 114 x 5/6 = 95
Roll 2: 95 x 5/6 = 79.17
Roll 3: 79.17 x 5/6 = 65.97
Roll 4: 65.97 x 5/6 = 54.98
Most likely to take 4 rolls before halving the number of dice.
You could also solve this problems by writing an equation and solving using logs but I think this method is easier to understand.
Hope this helped!
A 50-kg copper block initially at 140°c is dropped into an insulated tank that contains 90 l of water at 10°c. Determine the final equilibrium temperature and the total entropy change for this process.
Answer:
[tex]T_f=24.71[/tex]
Explanation:
From the question we are told that:
Mass of block [tex]m=50[/tex]
Temperature of block [tex]T_b =140 \textdegree C[/tex]
Volume of water [tex]V= 90L[/tex]
Temperature of water [tex]T_w=10 \textdegree C[/tex]
Density of water [tex]\rho=1000kg/m^3[/tex]
Specific heat of water [tex]C_w=4.18KJ/kg-k[/tex]
Specific heat of copper [tex]C_p=0.96KJ/kg-k[/tex]
Generally the equation for equilibrium stage is mathematically given by
[tex]mC_p(T_b-T_f)=\rho*VV*c(T_f-T_w)[/tex]
[tex]50*0.96(140-T_f)=1000*90*10^-3*c_w(T_f-10)[/tex]
[tex]48(140-T_f)=376.2(T_f-10)[/tex]
[tex]140-T_f=7.8375(T_f-10)[/tex]
[tex]140-T_f=7.8375T_f-78.375[/tex]
[tex]-8.8375T_f=-218.375[/tex]
[tex]T_f=\frac{-218.375}{-8.8375}[/tex]
[tex]T_f=\frac{-218.375}{-8.8375}[/tex]
[tex]T_f=24.71[/tex]
Which one of the following is an example of an acid-base reaction?
A. 2HCl + Mg(OH)2 + 2H2O + MgCl2
B. Fe + CuSO4 → FeSO4 + Cu
C. 2Li + ZnSO4 → Li2SO4 + Zn
O D. C5H12 + 802 - 5CO2 + 6H20
No links please
Answer:
A. 2HCl + Mg(OH)2 + 2H2O + MgCl2
hope it helps
8. What is the frequency heard by a person driving at 15.0 m/s toward a blowing factory whistle (800. Hz) if the speed of sound is 340.6 m/s? (837 Hz) F= (340.6×800)÷(340.6-15)= 836.9 Hz F=836.9 9. From the previous problem, what frequency would he hear after passing the factory if he continues at the same speed? (766 Hz)
Answer:
A) f_o ≈ 836.9 Hz
B) f ≈ 765 Hz
Explanation:
A) To solve this, we will use the formula;
f_o = (v•f_s)/(v - v_p)
Where;
v is speed of sound in air
f_s is frequency of source
v_p is the speed of the person moving towards the whistle.
We are given;
v = 340.6 m/s
v_p = 15 m/s
f_s = 800 Hz
Thus;
f_o = (340.6 × 800)/(340.6 - 15)
f_o ≈ 836.9 Hz
B) to solve this, let's first calculate the wavelength from the formula;
λ = v/f_s
λ = 340.6/800
λ = 0.42575 m
To get the frequency he will hear after passing the factory, we will use the formula;
f = (v - v_p)/λ
f = (340.6 - 15)/0.42575
f ≈ 765 Hz
Un movil avanza a 20 m/s y recorre una distancia de 800 km. Determinar el tiempo en horas que utiliza
Answer:
t = 11.1 hours
Explanation:
The question says that, "A mobile advances at 20 m / s and travels a distance of 800 km. Determine the time in hours you use".
Given that,
Speed of a mobile, v = 20 m/s = 72 km/h
Distance, d = 800 km
We know that,
Speed = distance/time
So,
[tex]t=\dfrac{d}{v}\\\\t=\dfrac{800}{72}\\\\t=11.1\ h[/tex]
So, it will take 11.1 hours.
Ali mixes 20g of Sodium Chloride in 100g of water at 15 Degree °C. Calculate the mass of the solution
Answer:
The mass of the solution is 120 g.
Explanation:
The mass of the solution is given by:
[tex] m_{sol} = m_{1} + m_{2} [/tex]
Where:
[tex]m_{sol}[/tex]: is the mass of the solution
[tex]m_{1}[/tex]: is the mass of the solvent
[tex]m_{2}[/tex]: is the mass of the solute
In the solution, the solvent is the majority compound (in mass) and the solute is the minority (in mass), so the solvent is the water and the solute is sodium chloride.
Hence, the mass of the solution is:
[tex] m_{sol} = m_{1} + m_{2} = 100 g + 20 g = 120 g [/tex]
I hope it helps you!
The lens of a telescope has a diameter of 25 cm. You are using it to look at two stars that are 2 × 1017 m away from you and 6 × 109 m from each other. You are measuring light with a wavelength of 700 nm. As the light goes through the lens, it diffracts. a. Is it possible, using this telescope, to see the two stars as separate stars? b. What is the minimum possible lens diameter you would need in order to resolve these two stars?
Answer:
a)It is NOT possible using this telescope, to see the two stars as separate stars
b)[tex]d_{min} =28.466m[/tex]
Explanation:
From the question we are told that:
Diameter of lens,[tex]d = 25 cm \approx 0.25 m[/tex]
Distance from both star [tex]D_f= 2*10^{17} m[/tex]
Distance between both stars [tex]D_b= 6*10^9 m[/tex]
Wavelength of light [tex]\lambda =700 nm \approx 700*10^-9 m[/tex]
Generally the equation for angle subtended by the two stars at the lens is mathematically given by
[tex]\theta=\frac{D_f}{D_b}[/tex]
[tex]\theta=\frac{6*10^9}{2*10^{17}}[/tex]
[tex]\theta=3.0*10^{-8} rad[/tex]
Generally the equation for minimum angular separation of two object is mathematically given by
[tex]\theta_{min} = 1.22*\lambda/d[/tex]
[tex]\theta_{min}= \frac{1.22*700*10^-9}{0.25}[/tex]
[tex]\theta_{min}= 3.416*10^-^6 rad[/tex]
Therefore
[tex]\theta < \theta_{min}[/tex]
[tex]3.0*10^{-8} rad< 3.416*10^-^6 rad[/tex]
It is NOT possible using this telescope, to see the two stars as separate stars
b)
Generally the equation for minimum diameter of the lens is mathematically given by
[tex]d_{min} =\frac{ 1.22*\lambda}{\theta}[/tex]
[tex]d_{min} =\frac{ 1.22*700*10^{-9}}{3*10^{-8}}[/tex]
[tex]d_{min} =28.466m[/tex]
What mistake did Kamala make? Gamma rays should have a very high frequency, not a very low frequency. Visible light should have a low frequency and a long wavelength. Infrared light should have a short wavelength, not a long wavelength. Microwaves should have a high frequency and a short wavelength.
Answer:
The answer is "Option A".
Explanation:
Please find the complete question in the attached file.
Kamala uses Gamma radiation inside this question should be very high, not very low. Electromagnetic radiation is a penetrating type resulting from radioactive nuclear decline. Its radiation is a very high-frequency, radioactive waveform to frequencies greater than [tex]10^{19} \ Hz[/tex] usually emitted from the radioactive decline.
Answer:
A
Explanation:
edge 2022
What conditions would probably exist the dew point and dry bulb temperatures to be the same at the ground ?
Answer: The conditions would probably exist the drew point and dry bulb temperatures to be the same at the ground because When the dew point temperature and air temperature are equal, the air is said to be saturated. Dew point temperature is NEVER GREATER than the air temperature. Therefore, if the air cools, moisture must be removed from the air and this is accomplished through condensation.
Explanation:
Since the air is said to be saturated when the dew point temperature and air temperatures are equal, the circumstances are likely present for the dew point and dry bulb temperatures to be equal at the ground. NEVER is the dew point temperature higher than that of the air temperature. As a result, condensation is used to remove moisture from the air when it cools.
What is dew point temperature?The dew point, under the assumption of constant air pressure and water content, is the temperature at which air must be chilled to become water vapor condenses. Airborne vapor will condense to create liquid water, known as dew, when it is cooled below the dew point, thereby moisture capacity. If this occurs via coming into contact with a cooler surface, dew will grow there.
Humidity influences the dew point. The dew point rises as the amount of moisture in the atmosphere increases.
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A book that weighs 20 N sits on a table. How big and in what direction does the force of gravity from the Earth act on the book?
A. 20 N down
B. 10 N down
C. 20 N up
D. 10 N up
Answer:
A. 20 N down
Explanation:
It's asking how much force of gravity is acting on it. The book weighs 20 Newtons so that's how much gravity is being applied. Hope this helps
When a book that weighs 20 N sits on a table. then the force of gravity from the Earth acts on the book would be 20 N down, therefore the correct option is A.
What is gravity?It can be defined as the force by which a body attracts another body towards its center as the result of the gravitational pull of one body and another, The gravity varies according to the mass and size of the body for example the force of gravity on the moon is the 1/6th times of the force of gravity on the earth.
When an object is thrown straight up in the absence of air resistance there is no external force acting on it except the gravitational force of the earth which very much reflects the fact that the acceleration due to gravity is constant and is the result of the gravitational pull of the earth which act on the downward direction.
A book that weighs 20 N sits on a table and faces a downward force of 20N acts on the book because the force of gravity from the Earth acts on the book.
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How are frequency, wavelength, and energy related? Choose all that apply.
Explanation:
The energy of a wave is given by :
[tex]E=\dfrac{hc}{\lambda}[/tex]
Where
h is Planck's constant
c is the speed of light
[tex]\lambda[/tex] is wavelength
Energy is inversely proportional to wavelength. Also, the relation between frequency and wavelength is inverse.
If the frequency is high, the wavelength will be shorter.
Hence, the correct options are :
Higher frequencies have shorter wavelengths.
Shorter wavelengths have lower energy.
Lower frequencies have lower energy.
which word meaning sensible has the most negative connotation
Answer:
I’d say stuffy. It has the most negative connotation of all the options .
Mark Brainlest please!
Studying this brochure from nasa, which explains more detail the instruments carried by the Juno spacecraft which scientific activities will jump conduct on its trip to Jupiter? Check all that apply
Answer:
Juno scientific payload includes:
A gravity/radio science system (Gravity Science) A six-wavelength microwave radiometer for atmospheric sounding and composition (MWR) A vector magnetometer (MAG) Plasma and energetic particle detectors (JADE and JEDI) A radio/plasma wave experiment (Waves) An ultraviolet imager/spectrometer (UVS) An infrared imager/spectrometer (JIRAM)Explanation:
Each mission of NASA has a specific set of instruments that it uses to perform scientific experiments on the desired heavenly body. In case of Juno, the mission for Jupiter has a series of instruments that would study domains of gravitational forces, magnetic effect, particle detection, radiation detection, UV/IR imaging, and plasma experiments.
Which product forms from the synthesis reaction between calcium (Ca) and
chlorine (CI)?
A. CaCl2
B. CaCl
C. Ca2Cl2
O D. Caci
SUBMIT
Answer:
CaCl2
Explanation:
Answer:
its a! the answer is a
Explanation:
Reo performed an experiment to investigate the strength of an electromagnet and the amount of force that would be affected by the size of the current flowing through its coils. Which of the following changes would increase the current flow the most?
a. Decreasing the number of paper clips being picked up
b. Decreasing the number of coils of wire wrapped around the nail
c. Increasing the voltage power supply
d. Increasing the number of nails
(WILL GIVE BRAINLIEST)
Answer:
b. Decreasing the number of coils of wire wrapped around the nail
it can cause an electrical current running through it creates a magnetic field.
Which of the following is evidence that a chemical reaction has occurred?
Several merchant ships reports rogue waves
which are estimated to be 25 meters high and 26 meters long. Assuming that these waves travel at
speeds of 6.5 m/s, determine the frequency and the period of these waves.
Answer:
The frequency is 0.25Hz and the period is 4s
Explanation:
To solve this we can use the formula: [tex]f = \frac{v}{\lambda}[/tex], where f=frequency, v=velocity and lambda = wavelength.
In the question, we are given the information that the velocity of the wave is 6.5m/s and the wavelength is 26 meters long. By putting these values into the formula, we can find the frequency:
[tex]f=\frac{6.5}{26} \\f= 0.25Hz[/tex]
Period is the inverse of frequency: [tex]T=\frac{1}{f}[/tex]
Therefore the period is: [tex]T = \frac{1}{0.25} \\T = 4s[/tex]
Hope this helped!
How many pieces of thin, light glass will have the same effect as one thick, dark glass?
Answer:
Explanation:
i would 3 thin light glass would have the same effect as one thick dark glass
Four pieces of thin, light glass will have the same effect as one thick, dark glass.
What is Glass ?Glass is an inorganic solid substance that is generally transparent or translucent, as well as hard, brittle, and resistant to the elements. From ancient times, glass has been used to make utilitarian and aesthetic products, and it is now highly significant in uses as diverse as building construction, kitchenware, and telecommunications. It is created by rapidly chilling molten components such as silica sand to prevent the creation of visible crystals.
A quick discussion on glass follows. A lot of articles go into great length on glass. Stained glass and glassware explain stained glass and the aesthetic qualities of glass design. Industrial glass discusses the composition, characteristics, and industrial manufacture of glass. The physical and atomic properties of glass are discussed in amorphous solid.
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