Answer:
Explanation:
[tex]a=\frac{v_f-v_0}{t}[/tex] We don't yet need the mass of the car, as we can see by this equation. What we do need is the velocity of the car, the initial velocity, in meters per second, and right now it's in km/hr. Not good. We need to convert. The conversion is as follows:
[tex]54\frac{km}{hr}*\frac{1000m}{1km}*\frac{1hr}{3600s}=15\frac{m}{s}[/tex] Ok, that's good. Now we have everything we need but the time element. If the car traveled a distance of 40 meters at 15 m/s, then we can use the d = rt equation to solve for t, and when we find t we plug it into the acceleration equation:
40 = 15t and
t = 2.7 seconds. The car traveled for 2.7 seconds to go that 40 meters. That's the only reason we were given the displacement. We need it for nothing else but that.
Filling in the acceleration equation now:
[tex]a=\frac{0-15}{2.7}=-5.6\frac{m}{s^2}[/tex] and the negative indicates we are in fact slowing down. That's the answer for the acceleration portion of the problem; now we need the force, F, applied to the brakes.
F = ma where m is mass (we get to use that value now!) and a is -5.6 m/s/s.
F = 500(-5.6) and
F = -2800 N and the negative here means that the force of the brakes is acting against the motion of the car: the brakes are pulling the car "backwards" to stop while the car's motion is forward. The negative indicates the direction the force is being applied.
Một con lắc lò xo gồm 1 quả nặng có m= 0,2kg treo vào lò xo có độ cứng k= 100N/m, cho vật dao động điều hoà theo phương thẳng đứng với biên độ A= 1,5 cm. Lực đàn hồi cực đại có giá trị
In a hydrogen atom, the electric force is the centripetal force. Determine the speed of an electron in orbit around a proton if the distance between them is 5.29 x 10^{-11} m. The mass of an electron is 9.11 x 10^-31 kg. (HINT: equate centripetal force and electric force)
Write down the conservation of momentum?
Global warming is threatening polar bear habitats and the bears' way of life. If trends continue, predict what will become of the polar bear in the next 10,000 years. Will it adapt or become extinct? Defend your answer.
Bear will become extinct due to global warming.
What is greenhouse gas?The gases which get easily trapped inside the glasses and increase the temperature of the atmosphere causing the global warming level to increase overall.
Global warming is threatening polar bear habitats and the bears way of life. If global warming continues, predict what will become of the polar bear in the next 10,000 years
Thus, bear will extinct.
Learn more about greenhouse gas.
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please answer fast..........
Answer:
The correct answer is a. Subsonic
Hope this helps you^_^
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Describe the laws of liquid pressure and explain the term fluid. (Please try to give the correct answer 'coz it's urgent!)
Answer:
The laws of liquid pressure are: ... The liquid pressure at a point inside the liquid is same in all directions. The liquid pressure at a point inside the liquid is directly proportional to the depth of that point from the free surface of liquid. The pressure of liquid at same depth is different for different liquids
Answer:
The laws of liquid pressure:
The pressure that is inside the liquid rises with the intensity from the surface of a liquid.
The term fluid:
Fluid is basically liquid and a substance that is known to have no certain shape. The opposite of the term fluid would be solid.
what is field selection process
It is a process of offering jobs to desired candidates and offering jobs to the desired applicant.
Un globo contiene 4 moles de un gas ideal con un volúmen de 5,0 L. Si se agregan 8 moles adicionales del gas a presión y temperatura constantes, ¿Cuál será el volumen final del globo? - ¿Cuál es la densidad (en g / L) de un gas con una masa molar de 60 g / mol a 0,75 atm y 27 ° C?
Tenemos un problema de termodinamica sobre gases ideales, los cuales pueden ser descritos por la ecuación de estado del gas ideal
[tex]P*V = n*R*T[/tex]
donde:
P = presión
V = volumen
n = número de moles
R = constante de los gases
T = temperatura.
1) Para el primer problema podemos pensar que el gas dentro del globo es un gas ideal:
Originalmente sabemos que n = 4 y V = 5.0 L
Entonces tendremos:
[tex]P*(5.0 L) = (4 moles)*R*T[/tex]
Ahora decidimos agregar 8 moles más, dejando constante la presión y la temperatura, entonces podemos reescribir la ecuación de arriba como:
(5.0L)/(4 moles) = R*T/P
Y como R, T y P son constantes, entonces:
R*T/P es una constante.
Esto quiere decir que cuando agreguemos 8 moles, para tener un total de 12 moles, tendremos que:
V'/(12 moles) = R*T/P = (5.0L)/(4 moles)
Donde V' es el nuevo volumen final del globo, y es lo que queremos obtener.
V'/(12 moles) = (5.0L)/(4 moles)
V' = (5.0L)*(12 moles)/(4 moles) = (5.0 L)*3 = 15.0 L
2) Queremos obtener la densidad en gramos sobre litro de un gas con una masa molar de 60g/mol, a P = 0.75 atm y T = 25°C.
Primero pasemos la temperatura a grados kelvin:
T = 25°C = (25 + 273.15)°K = 298.15°K
Planteamos la ecuación del gas ideal:
[tex]P*V = n*R*T[/tex]
reemplazando R = 0.082 (atm*L/mol*k), además de la presión y la temperatura para un solo mol de gas:
[tex](0.75 atm)*V = (1 mol)*(0.082 (atm*L/mol*k))*(298.15°K)[/tex]
Resolviendo para V obtenemos que:
[tex]V = (1 mol)*(0.082 (atm*L/mol*k))*(298.15°K)/(0.75 atm) = 32.597 L[/tex]
Así, vemos que un mol de este gas ocupa un volumen de 32.597 L
Y también sabemos que un mol de este gas pesa 60 gramos.
Recordando que la densidad es el cociente entre la masa y el volumen, podemos ver que la densidad del gas será:
[tex]d = 60g/(32.597 L) = 1.84 g/L[/tex]
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a.
quuntlity.
Answer the following questions.
What is force? Write down its SI unit.
b. Name
any five types of force.
c.
What is pulling force? Give any two examples.
d. What is centripetal force? Give one example of centrifugal force.
What is gravitational force? Give two examples.
f. What is magnetic force? How is this force useful to us?
Answer:
1) Force is the action of pull or push that changes or tends to change the position of a body. Its SI unit is newton.
2) The types of force are:
• Pulling and Pushing force
• Frictional force
• Gravitational force
•Muscular force
• Centripetal and Centrifugal force
Please help
I can’t get this right
Answer:
6,76 x 10^-7 T.
Explanation:
The Magnetic field formula for a wire is B=(μ x I)/2πd , where μ (=4π x 10^-7 Tm/A) is the permeability, I is the current and d is the distance.
Write the dimension of a / b in the x = at + bt2. Where x is the distance and t is the time?
The dimension of a/b where x is the distance and t is the time is T
Given the expression
x = at + bt²
where
x is the distance
t is the time
Based on the homogeneity principle, the expression on the left-hand side must be equal to that on the right. Hence;
x = at
[tex]a = \frac{x}{t}[/tex]
Since x is the distance and distance is measured in metres, the dimension equivalent will be the length 'L'
Since t is the time and time is measured in seconds, the dimension equivalent will be the seconds 'T'
[tex]a=\frac{L}{T}[/tex]
Similarly;
x = bt²
[tex]b=\frac{x}{t^2}\\b=\frac{L}{T^2}[/tex]
Next is to get a/b;
[tex]\frac{a}{b} = \frac{L}{T} \div \frac{L}{T^2}\\\frac{a}{b} = \frac{L}{T}*\frac{T^2}{L} \\\frac{a}{b} =\frac{T^2}{T}\\\frac{a}{b} =T[/tex]
Hence the dimension of a/b is T
out of solid and liquid which has more effect on gravitation
Answer:
The effect of gravitation is more in liquid than on solid because inter molecular force of attraction is less in liquid and it is weak than that of solid. ... Whereas in solid the molecule are densely packed together an the inter molecular forces are constantly acting upon one another, this results in higher forces.
Which law states that absolute zero cannot be reached?
why do the other animals listen to old major speak in the barn late on night?
2) Define volume. Explain in detail how can volume of irregular object be determined?
PLZ HELP NEED THIS RN
The three dimensional space of a body is called volume
explain why resistors connected in parallel are called current dividers
Explanation:
A parallel circuit is often called a current divider for its ability to proportion—or divide—the total current into fractional parts. Once again, it should be apparent that the current through each resistor is related to its resistance, given that the voltage across all resistors is the same
Lightning a. occurs when a positively charged cloud base induces a negative charge on the Earth's surface. b. travels most often from cloud to ground and cannot travel from cloud to cloud. c. may be accompanied by the sound of explosively expanding hot air, called thunder. d. involves a conductive path or leader of positive ions from cloud to ground.
Answer:
c. may be accompanied by the sound of explosively expanding hot air, called thunder.
Explanation:
Lightning is a discharge which is due to the reaction between oppositely charged charges in the clouds, or between clouds base and the Earth surface.
The motion of the cloud causes charging of clouds by friction, thus the reaction between opposite charges (jumping of charges from one cloud to another) in the cloud can lead to lightning. Also, oftentimes the bottom of a cloud is negatively charged so that this is attracted to the positive charge on the earth surface. Thus leading to a discharge called lightning.
Thus in the given question, the appropriate option is C. This implies that, lightning may be accompanied by the sound of explosively expanding hot air, called thunder.
Động vật nào sau đây máu đi nuôi cơ thể không pha trộn giữa máu giàu O2 và máu giàu CO2?
A.
Bò sát, chim, thú
B.
Cá, bò sát, chim
C.
Cá, lưỡng cư, bò sát
D.
Cá, chim, thú
Answer:
D
Explanation:
Cá xương, chim, thú, cá sấu không có sự pha trộn máu giàu O2 và máu giàu CO2 ở tim vì tim cá có 2 ngăn, tim các loài chim, thú, cá sấu có 4 ngăn
why does apparent depth of different liquids vary
Define derived unit with example
Answer:
A derived unit is a SI unit of measurement comprised of a combination of the seven base units. Like SI unit of force is the derived unit, newton or N where N=s21×m×kg. There are some commonly used derived units which includes: 1. Pressure = AreaForce=m2N.
Explanation:
Which of the following is a vector quantity? i. Force ii. Velocity iii. Acceleration iv. All of these 5771
Option ( iv ) is the correct answer.
☛ DefinitionA vector quantity the physical quantity that has both direction as well as magnitude.
A rocket travels 1.3 km in 62 ms. What is its average speed in m⋅s−1? Do not give your answer in scientific notation. The answer should be given to 2 significant figures.
Answer:
Average speed = 0.35 m/s
Explanation:
Given the following data;
Distance = 1.3 Km
Time = 62 minutes
To find the average speed in m/s;
First of all, we would convert the quantities to their standard unit (S.I) of measurement;
Conversion:
1.3 kilometres to meters = 1.3 * 1000 = 1300 meters
For time;
1 minute = 60 seconds
62 minutes = X
Cross-multiplying, we have;
X = 62 * 60
X = 3720 seconds
Now, we can calculate the average speed in m/s using the formula;
[tex] Speed = \frac {distance}{time} [/tex]
[tex] Speed = \frac {1300}{3720} [/tex]
Average speed = 0.35 m/s
By how many times will the kinetic energy of a body increase if its speed is tripled? Show by calculation .
Answer:
9 lần
Explanation:
Answer:
Kinetic energy (k.e) varies directly as v² from the formula
K.E=(mv²/2)
if v=3 then K.e =v²=(3)²=9
state any two effects of gravitational force
Answer:
The effect of gravity extends from each object out into space in all directions, and for an infinite distance. However, the strength of the gravitational force reduces quickly with distance. Humans are never aware of the Sun's gravity pulling them because the pull is so small at the distance between the Earth and Sun.
Answer:
The Earth's gravitational force accelerates objects when they fall. It constantly pulls, and the objects constantly speed up.
Explanation:
Describe an experiment to find the volume of an irregular- shaped ston
One way to measure the volume of any irregular object (in your case, a stone) is to submerge it completely under water and measure the change in the height of the water level. This change in the water level (let's say it goes from 50 mL to 65 mL) indicates that the stone has a volume of 15 mL .
balance the following equations: CUCO3+H2SO4- CUSO4+H2O+CO2
Answer:
It is already balanced
Explanation:
It is already balanced
What are the units for speed?
O A. km/s2
O B. m/s2
O C. m/s2
O D. m/s
Answer:
Explanation:
The only one that doesn't have a time unit that is squared is the one that is a label for speed or velocity. Acceleration has a label with the time unit squared, like m/s/s. Choice D is the only unit for speed/velocity.
Answer: D
Explanation: metres per second (m/s)
The spectra of most galaxies show redshifts. This means that their spectral lines Group of answer choices always are in the red part of the visible spectrum. have wavelengths that are longer than normal. have a higher intensity in the red part of the spectrum. have wavelengths that are shorter than normal.
have a higher intensity in the red part of the spectrum
Because of the Doppler effect, the spectra of most galaxies show redshifts. This means that their spectral lines Group of answer choices always are in the red part of the visible spectrum
Most galaxies' spectra have been redshifted, which means that their spectral lines are now pushed away from their normal or rest wavelengths and towards longer wavelengths. When an object travels away from an observer, the Doppler effect causes the shift phenomenon.
The Big Bang hypothesis and the concept of the expanding universe, show that galaxies are moving away from us, observed from the redshift lines.
The waves' apparent wavelengths shift as a result, changing the color of light waves or the pitch of sound waves.
Hence, because of the Doppler effect, the spectra of most galaxies show redshifts. This means that their spectral lines Group of answer choices always are in the red part of the visible spectrum.
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Current is the movement of positive charges called electrons.
A. True
B. False
help pls <33
Answer:
False -> negative charge
Answer:
false
Explanation: electrons are negative charges
protons are positive charges
PLEASE HELP MAX POINTS AND BRAINLIEST!
Look at the graph below.
A graph is shown with Absolute magnitude shown on the y-axis and Surface temperature in degree Celsius shown on the x-axis. The Dwarf stars are shown along a slanting line from coordinates 30,000 and minus 3 to 10,000 and minus 4. The Main Sequence stars are shown along a slanting line from coordinates 20,000 and minus 2 to 2,000 and minus 6. The giants are shown along a line parallel to the x-axis from coordinates 5,000 and 2 to 2,000 and 3. The supergiants are shown along a line parallel to the x-axis from coordinates 7,500 and 4 to 2,500 and 4. Point A has coordinates 20,000 and minus 4. Point B has coordinates 2,500 and minus 4. Point C has coordinates 5,000 and 2. Point D has coordinates 7,000 and 4.
Which of the following stars is most likely to be red?
a. Star A
b. Star B
c. Star C
d. Star D
i believe it would be Star A since Point A is a dwarf star and dwarf stars are usually most likely to have red coloring
Answer:
Star A
Explanation:
Literally the question has provided the answer itself
Calculation not required.
See the wordings
First star is dwarf star .
Dwarf star is mostly reddish brown or red colored .
Hence star A is the answer
