Answer:
b. 4.6 %
Explanation:
From the question,
E = M.A/V.R................ Equation 1
Where E = percentage Efficiency of the machine, M.A = machanical accurancy of the machine, V.R = Velocity ratio of the machine
Make V.R the subject of the equation
V.R = M.A/E
Given: M.A = 3, E = 65% = 0.65
Substitute this values into equation 2
V.R = 3/0.65
V.R = 4.6
Hence the right option is b. 4.6 $
'If you increase the frequency of a sound wave four times, what will happen to its speed?
ОА.
The speed will increase four times.
OB.
The speed will decrease four times.
O c.
The speed will remain the same.
OD
The speed will increase twice.
O E.
The speed will decrease twice.
Explain why, in terms of forces, there is a risk of head injury when diving from this height. Suggest why the high divers would choose to enter the water feet first.
Answer:
Due to lower risk of injury or damage.
Explanation:
The high divers would choose to enter the water from the feet first because there is low risk of injury. The brain is the most important part of the body which very sensitive to any small injury. Small injury to brain leads to big problems in life. High divers can reach speeds of nearly 60 mph and enters about 28m into the water in about three seconds which can damage the head region if comes in contact with the ground so this is the reason the high divers avoid of entering in the water through their heads and choose entering through their feet.
A police car is driving north with a siren making a frequency of 1038 hz. Moops is driving north behind the police car at 12 m/s and hard a frequency of 959hz. How fast is the police car going?
Answer:
The police car is moving at 41.24 m/s.
Explanation:
To find the speed of the police car we need to use the Doppler equation:
[tex] f = f_{0}(\frac{v + v_{r}}{v + v_{s}}) [/tex]
Where:
v: is the speed of the sound = 343 m/s
[tex]v_{r}[/tex]: is the speed of the receiver = 12 m/s
[tex]v_{s}[/tex]: is the speed of the source =?
f: is the observed frequency = 959 Hz
f₀: is the emitted frequency = 1038 Hz
Both terms are positive in the fraction because the velocity of the sound is in the opposite direction to both velocities of the police car and the other car.
By solving the above equation for [tex]v_{s}[/tex] we have:
[tex] v_{s} = \frac{f_{0}(v + v_{r})}{f} - v = \frac{1038(343 + 12)}{959} - 343 = 41.24 m/s [/tex]
Therefore, the police car is moving at 41.24 m/s.
I hope it helps you!
Two 10.-ohm resistors have an equivalent resistance of 5.0 ohms when connected in an electric circuit with a source of potential difference. Using circuit symbols found below, draw a diagram of this
circuit.
The resistors are connected in parallel between the terminals of a battery.
Note: If those resistors are connected in parallel, then their equivalent resistance is already 5 ohms, even if they're still in the drawer or in a box on the shelf. They don't have to be connected to a source of voltage for that to happen.
Use the drop-down menus to complete the statements. Outlook allows users to insert symbols and characters not located on the , but they can have shortcut keys. Inserting horizontal lines in the message body breaks up different sections and mostly benefits people using Outlook on .
Answer:
Keyboard and Mobile devices
Explanation:
got it right on edge 2021
Answer:
Outlook allows users to insert symbols and characters not located on the
keyboard
, but they can have shortcut keys.
Inserting horizontal lines in the message body breaks up different sections and mostly benefits people using Outlook on
mobile devices
.
Explanation:
yo i really need help please in order to pass this i’ll give a brainliest to anyway who knows the correct answer please no links
You toss a ball straight up into the air. Assume that air resistance is negligible.
PART A. Draw a free-body diagram for the ball at three points: on the way up, at the top, and on the bottom, and on the way down. Specifically identify the forces and agents acting on the ball.
PART B. What is the ball's velocity at the very top of the motion?
PART C. What is the ball's acceleration at this point?
Answer:
the answer is B I promise
What is the full meaning of ROYGBIV?
Answer:
Red, orange, yellow, green, blue, indigo and violet.
Explanation:
Hope I helped! cute copy and paste ☏ ♡ ☆⋆◦★◦⋆°*•°
. * . . ° . ● ° .
¸ . ★ ° :. . • ° . * :. ☆
° :. ° .☆ . ● .° °★
★ ★°★ . * . °☆ . ● . ★ ° . • ○ ● . ☆ ★ ° ☆ ¸. ¸ ★ . • ° . *
¸ . ★ ° :. :. . ¸ . ● ¸ ° ¸. * ● ¸ °☆
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° :. ° . ☆ . . • . ● .° °★ Not sure how to copy and paste? Just right click your mouse and choose copy in options, to release repeat the process and just paste it. No mouse? Select the text with your computer pad and use ctrl c to release, ctrl v. On mobile? Press on your screen and select the text, use the option copy and paste wherever you would like!
⭐ Hii ⭐
➡️ Abbreviation for shades of colors often described as creating rainbows: red, orange, yellow, green, blue, indigo, and violet. Its beginning is sometimes called VIBGYOR in reverse order.
Byy...
Why might a scientist use a magnet and small strainer when investigating the physical properties of a substance?
Answer:
In order to check its magnetic properties and for removing impurities.
Explanation:
A scientist use a magnet and small strainer while investigating the physical properties of a substance in order to check the magnetic properties of the substance as well as to separate the substance from the other impurities. Magnet attract substances that is made of metals or magnetic characteristics while on the other hand, small strainer is used to separate impurities from the investigating substance so that's why the scientist use a magnet and small strainer during investigation of a substance.
A scientist use a magnet to check magnetic properties of the substance and use small strainer to separate the substance from the other impurities.
The magnet have Attractive Property , Magnet attracts ferromagnetic materials like iron, cobalt, and nickel.Magnet attract substances that is made of metals or magnetic characteristics .The small strainer is used to separate impurities from the investigating substanceLearn more:
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Show that liquid pressure is directly
proportional to height of liquid in a vessel.
Answer:
P=F/A where F is the weight of the water and A is the area on which it is resting. The weight of the water is mg. The mass of the water is dv where d is the density and v is the volume. Finally, the volume of the water in a vessel is equal to the area of the base of the vessel times the height of the vessel. (v=Ah)
Plugging everything in we get:
P = dAhg/A
So
P=dhg
So we have shown that liquid pressure is directly proportional to height of liquid in a vessel.
Which statement describes the redox reaction involved in photosynthesis?
A. It transfers energy to ATP molecules so energy can be transferred.
B. It is a combustion reaction in which energy is released.
C. CO2 is removed from the atmosphere, and O2 is released
D. O2 is removed from the atmosphere, and CO2 is released
The statement 'CO2 is removed from the atmosphere, and O2 is released' describes the redox reaction involved in photosynthesis. It is a redox reaction.
What is photosynthesis?
Photosynthesis refers to a series of reactions by which plants can produce simple carbohydrates by using solar radiation and oxygen (O2).
These photosynthetic reactions are well known to release carbon dioxide (CO2) into the atmosphere.
During Photosynthesis, CO2 is reduced to simple carbohydrates (e.g., glucose), while water (H2O) is oxidized to O2, thereby producing a redox reaction.
Learn more about Photosynthesis here:
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In a real pully system the work supplied must be _____ the work accomplished and no links plz
PLEASE HELP MEEEE
The bending of waves due to a change in speed is called
a.
reflection.
b.
refraction.
c.
diffraction.
d.
interference.
Answer:
D
Explanation:
Interference is the interaction between waves that meet.
In its elemental state, carbon is available as:
a
Coal
b Graphite
C Diamond
All of the above
Answer: D all of the above
Explanation: Coal, Graphite, Diamond are all allotropes of Carbon. Hope this helps :)
Which of the following are the two factors used to calculate average
speed? *
a. total acceleration and total time
b. velocity and time
c. total distance and total time
d. motion and time
Answer:
i think its its c but im not positive :>
Explanation:
The resistance of resistor is greater for:
a.Short and thin resistor
b.Short and thick resistor
c.Long and thin resistor
d.None
Answer:
c: long and thin resistor.
Explanation:
The resistance of a resistor is given by:
R = ρ*L/A
where:
R = resistance
ρ = resistivity (depends on the material)
L = length of the material
A = cross-sectional area of the material
We can see that the length is on the numerator, which means that if we increase the length, then the resistance is increased.
We also can see that the cross-sectional area is on the denominator, then if we increase the area (for example, with a ticker resistor) the resistance decreases.
Then if we want to maximize the resistance, we need to have a long and thin resistor, so the correct answer is c.
A football thrown by a professional quarterback goes farther than one thrown by a 10-year old. What Newton Law is this?
Answer:
2nd law of motion
Explanation:
Answer:
Newton's 2nd Law of Motion
Explanation:
The amount of force needed to make an object change its acceleration depends on the mass of the object. In other words, the amount of force thrown by a professional quarter-back has more acceleration from his mass.
Which best describes the energy of a sound wave as it travels through a medium?
It increases.
lt decreases.
It remains the sam.
It depends on the medium,
Answer:
it depends on the medium :D
What makes water a natural resource?
A.
It is a natural material that can be easily replaced.
B.
It is a material found in nature that people can use.
C.
It is a material that people can easily make and use.
D.
It is a energy source that cannot be replaced.
Answer:
I belive is the answer is B. It is a material found in nature that people can use. Because water is technically a natural resource.
A 13 500 N car traveling at 50.0 km/h rounds a curve of radius 2.00 × 102 m. Find the following: a. the centripetal acceleration of the car b. the centripetal force c. the minimum coefficient of static friction between the tires and the road that will allow the car to round the curve safely
Answer:
a. 0.947 m/s^2
b. 1304.54 N
c. 0.0966
Explanation:
mass of car = 13500 N = 13500/9.8 = 1377.55 kg
velocity = 50 km/h = 50,000 m/h = 13.9 m/s
raidus = 204 m
a. centripetal acceleartion = v^2/r = 13.9^2/204 = 0.947 m/s^2
b. centripetal force = m*centripetal acceleration = 1377.55 * 0.947 = 1304.54 N
c. In order for the car to round the curve safely, static friction = centripetal force
static friction = coefficient of friction (mu) * mg = mu* 1377.55*9.8 = 13500mu
13500mu = 1304.54
mu = 1304.54/13500 = 0.0966
The acceleration, force and coefficient of friction is required.
Centripetal acceleration is [tex]0.965\ \text{m/s}^2[/tex]
Centripetal force is [tex]1328\ \text{N}[/tex]
Coefficient of friction is [tex]0.1[/tex]
N = Weight of car = 13500 N
v = Velocity = [tex]50=\dfrac{50}{3.6}=13.89\ \text{m/s}[/tex]
r = Radius = [tex]2\times 10^2\ \text{m}[/tex]
m = Mass of car = [tex]\dfrac{N}{g}[/tex]
g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]
Centripetal acceleration is
[tex]a_c=\dfrac{v^2}{r}\\\Rightarrow a_c=\dfrac{13.89^2}{2\times 10^2}\\\Rightarrow a_c=0.965\ \text{m/s}^2[/tex]
Force is given by
[tex]F_c=ma_c\\\Rightarrow F_c=\dfrac{N}{g}a_c\\\Rightarrow F_c=\dfrac{13500}{9.81}\times 0.965\\\Rightarrow F_c=1328\ \text{N}[/tex]
Coefficient of friction is given by
[tex]\mu=\dfrac{F_c}{N}\\\Rightarrow \mu=\dfrac{1328}{13500}\\\Rightarrow \mu=0.098\approx 0.1[/tex]
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An entertainer pulls a table cloth off a table leaving behind the plates and sliverware undisturbed is an example of
A.
the law of balanced forces
B.
Newton's second law
C.
Newton's third law
D.
Newton's first law
Answer:
d.) Newton's first law
Explanation:
This is also called the law of inertia, which means that an object in motion will not stop unless a force is acted upon it, and vice versa. Try this out with a piece of paper and a quarter. Pull the paper from under the quarter slightly quick, and the quarter will stay on the table. Hope i helped you.
How does burning wood compare to the chemical reactions in trees that make them grow?
Answer:
Log burning in a fire. Burning wood is an example of a chemical reaction in which wood in the presence of heat and oxygen is transformed into carbon dioxide, water vapor, and ash.
Explanation:
While operating at 120 volts, an electric toaster has a resistance of 15 ohms. The power used by the toaster is
Answer:
960 Watt
Explanation:
From the question,
Electric power = Voltage squared/Resistance
P = V²/R ..................... Equation 1
Where P = power, V = Voltage, R = Resistance
Given: V = 120 volts, R = 15 ohms.
Substitute these values into equation 1
P = 120²/15
P = 14400/15
P = 960 Watt
1.45 L of 16°C water is placed in a refrigerator. The refrigerator's motor must supply an extra 10.7 W power to chill the water to 6°C in 0.7 hr. What is the refrigerator's coefficient of performance?
Answer:
The coefficient of performance of the refrigerator is 2.251.
Explanation:
In this case, the coefficient of performance of the refrigerator ([tex]COP[/tex]), no unit, is equal to the ratio of the heat rate received from the water to the power needed to work, that is:
[tex]COP = \frac{\dot Q_{L}}{\dot W}[/tex] (1)
[tex]COP = \frac{\rho\cdot V\cdot c_{w}\cdot \Delta T}{\dot W \cdot \Delta t}[/tex] (2)
Where:
[tex]\dot Q_{L}[/tex] - Heat rate received from the water, in watts.
[tex]\dot W[/tex] - Power, in watts.
[tex]\rho[/tex] - Density of water, in kilograms per cubic meter.
[tex]V[/tex] - Volume of water, in cubic meters.
[tex]c_{w}[/tex] - Specific heat of water, in joules per kilogram-degree Celsius.
[tex]\Delta T[/tex] - Temperature change, in degrees Celsius.
[tex]\Delta t[/tex] - Cooling time, in seconds.
If we know that [tex]\rho = 1000\,\frac{kg}{m^{3}}[/tex], [tex]V = 1.45\times 10^{-3}\,m^{3}[/tex], [tex]c_{w} = 4187\,\frac{J}{kg\cdot ^{ \circ}C}[/tex], [tex]\Delta T = 10\,^{\circ}C[/tex], [tex]\dot W = 10.7\,W[/tex] and [tex]\Delta t = 2520\,s[/tex], then the coefficient of refrigeration of the refrigerator is:
[tex]COP = \frac{\rho\cdot V\cdot c_{w}\cdot \Delta T}{\dot W \cdot \Delta t}[/tex]
[tex]COP = 2.251[/tex]
The coefficient of performance of the refrigerator is 2.251.
2. One of the cultural benefits of the ecosystems is:
A.flood prevention
B. recreation
C. climate moderation
D. erosion reduction.
Explanation:
Cultural Ecosystem Services (CES) are the non-material benefits people obtain from nature. They include recreation, aesthetic enjoyment, physical and mental health benefits and spiritual experiences. They contribute to a sense of place, foster social cohesion and are essential for human health and well-being.
What happens to the volume of sound as the amplitude gets larger?
A common way to measure the distance to lightning is to start counting, one count per second, as soon as you see the flash. Stop counting when you hear the thunder and divide by five to get the distance in miles. Use this information to estimate the speed of sound in m/s. Show your work below. This will require some conversions.
Answer:
d = 1.07 mile
Explanation:
The rationale for this method is that the speed of light is much greater than the speed of sound, the definition of speed in uniform motion is
v = d / t
d = v t
the speed of sound is worth
v = 343 m / s
Therefore, the speed of sound must be multiplied by time to do this, all the units must be in the same system, as the distance in miles is requested
v = 343 m/s (1mile/1609 m) (3600s/1 h) = 343 (2.24) = 767.4 mile/h
v = 343 m / s (1 mile / 1609 m) = 0.213, mile/ s
If the measured time is t = 5s we multiply it by the speed
we substitute
d = 0.213 5
d = 1.07 mile
If you want to calculate the speed, this method in general is not widely used, since you must know the distance where the lightning occurred, which is relatively complicated.
PLS ANWSER FAST WILL GIVE BRAINL!!!!
Explain to me in YOUR own words, how convection currents create a cycle? In other words, tell me how heat and cooling create a cycle.
Answer:
because it get the energy from the heat and the cold mixed together
Explanation:
What happens, if anything, when you change the mass of the planet? Why do you think the mass of the planet does, or does not, affect the orbit of the planet?
Answer:
We know that the gravitational force between two objects of mass M1 and M2 that are at a distance R, is given by:
F = G*(M1*M2)/R^2
Where G is a constant.
If you reduce one of the masses, then the gravitational force between the objects will change.
So if we take un account the Earth and the Sun, when you reduce the mass of Earth, the force between Earth and the Sun will decrease, and this will change the orbit of the Earth around the Sun.
(The orbit also depends on the gravitational force between the Earth and the other planets in the system, and all those forces also change, which also has an impact in the orbit change)
If the Sun, Earth, and Moon are lined up as shown, the Earth would have______.
A. Spring tides where there is almost no difference in the tides
B. Spring tides, which is where there are very high tides and very low tides
C. Neap tides where there is almost no difference in the tides.
D. Neap tides, which is where there are very high tides and very low tides
Answer:
The answer is B. Spring tides, which are where there are very high tides and very low tides.
Explanation:
Spring tides occur when the sun and the moon are in alignment with Earth.
At the time of a new moon or full moon when the sun, earth, and the moon are in full alignment the solar tide affects the lunar tide leading to the creation of extra-high high tides, and very low, low tides. The basic reasons for this phenomenon are the gravity of the sun and the moon is acting on the earth oceanPlease thank my answer and vote. (Maybe mark brainliest please)
Explain what does a calorimeter measure?
Measuring the heat of chemical reactions or physical changes.
