A fish inside the water 12cm below the surface looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3 the radius of circle is
Answers
Answer:
13.6 cm
Explanation:
From Snell's law:
n₁ sin θ₁ = n₂ sin θ₂
In the air, n₁ = 1, and light from the horizon forms a 90° angle with the vertical, so sin θ₁ = sin 90° = 1.
Given n₂ = 4/3:
1 = 4/3 sin θ
sin θ = 3/4
If x is the radius of the circle, then sin θ is:
sin θ = x / √(x² + 12²)
sin θ = x / √(x² + 144)
Substituting:
3/4 = x / √(x² + 144)
9/16 = x² / (x² + 144)
9/16 x² + 81 = x²
81 = 7/16 x²
x ≈ 13.6
Related Questions
fill in the blanks
1.)Seed drill is used for ____ of the seeds.
2.)ploughing helps the_____of roots of the growing plants.
3.)Tilling of the soil is also called a ________.
4.)Manure and fertilizers are use ti maintain the______of the soil.
5.)A most common weedicide is________.
6.)After harvesting,grains are separated from the chaffand hay by _______ or by using ______.
7.)The economial methods of irrigation are_____and____.
8.)The wild plants which grow along with the main crop are called_________.
9.) Shifting of tiny plants from a nursery to the main field is called______.
10.) Excess water and wet soil do not permit proper_____of the seeds or roots of the plants.
Answers
Answer:
1.) Sowing
2.) Respiration
3.) Soil preparation or cultivation or ploughing
4.) Fertility
5.) 2, 4 -D
6.) winnowing threshers
7.) Surface irrigation and sprinkler irrigation
8.) Weeds
9.) Transplantation
10.) Aeration
Explanation:
1.) Seed drill sows crop seed
2.) Ploughing assist in the respiration and penetration of the roots of a growing plants
3.) Tilling the soil is breaking of the soil lumps and turning of the soil
4.) Manure and fertilizers supply nutrient to the soil for the uptake by plant in food production
5.) 2, 4 -D are a range of weedicide containing 2,4-D as the active ingredient
6.) Winnowing is the separation of grain from straw
Threshers remove seeds from husks and stalks
7.) Surface irrigation -gravity enables the flow of the water
and sprinkler irrigation- Use of preset tools for irrigation
8.) Weeds are the unwanted, in situ, growing plants close to the crops
9.) Transplantation is the method of relocating plants
10.) Excess water limits access of the roots and seeds to atmospheric oxygen
is the body temperature of every person 37 degree Celsius. Why?
Answers
Answer:
Scientists have found the reason why our body temperature is 98.6°farehenheit (37°c). Apparently it's the perfect balance as it's warm enough to prevent fungal infection but not so hot that we need to eat nonstop to maintain our metabolism. ... So we know we need a higher body temperature to ward off fungal infection.
Using your own words, tell me
what is the difference between an Pure Substance and a Mixture? Make sure to give me an example of each.
Answers
Answer:
Hey there!
Mixtures are physically combined and can be separated. For example, sand and water is a mixture.
Pure substances are samples of matter with definite, and unchangeable chemical properties. For example, diamond is a pure substance.
Let me know if this helps :)
a pure substance is a substance that has not been mixed with anything, a mixture has been mixed with another substance. an example is
dirt +water=mud iron is an example of a substance
High voltage power is often carried in wire bundles made up of individual strands. In your initial post to the discussion, discuss the forces on the strands of wire due to the current flowing through them. What would happen if the force acted opposite of the known behavior? Provide a detailed description.
Answers
Answer:
There will be a huge problem of holding the wire strands together, and the power losses will also be amplified.
Explanation:
The force per unit length on two current carrying conductors, lying parallel to each other is proportional to the product of the current through the conductors, and inversely proportional to their distance apart. This force is attractive if the current flows through these conductors in the same direction, and is repulsive if it flows in the opposite direction.
For the strand of wire that make up a high voltage wire bundle, there will be a force of attraction pulling the wires closer to each other, and they will experience the maximum pulling force possible, since they lie next to each other. This force helps to hold these wires in a high tension wire strand together, limiting the area, and reducing "skin effect."
In the case that this wires in the wire strand acts in opposite of the known behavior, the wires will repel and push each other apart. This pushing apart will increase power loss due "skin effect" which is increased by an increase in exposed surface area of the wire strands. This will pose a big problem for high tension transmission.
an astronaut takes a tuning fork with her to the moon she strikes it inside the cabin the cabin is normally filled with air so the humans inside the spacecraft are comfortable she also strikes it outside the spacecraft when she gets down on the surface of the moon which of the following is true about the tuning fork?
A: it does not vibrate inside the spacecraft
B: id does not vibrate on moon surface
C: it vibrations are not transmitted inside the spacecraft
D:it's vibrations are not transmitted to the moon's atmosphere
Answers
Answer:
The correct option is;
D: Its vibrations are not transmitted to the moon's atmosphere
Explanation:
A tuning fork is used to produce sound by vibration such that the tune produced is pure
The tune, sound, produced by the tuning fork is transmitted as sound wave through the air by means of the gases of the air as a transmission medium so people at a distance that have air around them can hear the tuning fork sound
On the Moon's surface, the atmosphere is very and it is referred to technically as an exosphere, so the sound of the tuning fork has no medium through which to transmit and therefore, it is not transmitted on the Moon's atmosphere.
As a way of determining the inductance of a coil used in a research project, a student first connects the coil to a 5.62 V battery and measures a current of 0.698 A. The student then connects the coil to a 35.1 V(rms), 93.1 Hz generator and measures an rms current of 0.36 A. What is the inductance
Answers
Answer:
Its inductance L = 166 mH
Explanation:
Since a current, I = 0.698 A is obtained when a voltage , V = 5.62 V is applied, the resistance of the coil is gotten from V = IR
R = V/I = 5.62/0.698 = 8.052 Ω
Since we have a current of I' = 0.36 A (rms) when a voltage of V' = 35.1 V (rms) is applied, the impedance Z of the coil is gotten from
V₀' = I₀'Z where V₀ = maximum voltage = √2V' and I₀ = maximum current = √2I'
Z = V'/I' = √2 × 35.1 V/√2 × 0.36 V = 97.5 Ω
WE now find the reactance X of the coil from
Z² = X² + R²
X = √(Z² - R²)
= √(97.5² - 8.05²)
= √(9506.25 - 64.8025)
= √9441.4475
= 97.17 Ω
Now, the reactance X = 2πfL where f = frequency of generator = 93.1 Hz and L = inductance of coil.
L = X/2πf
= 97.17/2π(93.1 Hz)
= 97.17 Ω/584.965 rad/s
= 0.166 H
= 166 mH
Its inductance L = 166 mH
You have a hot reservoir held at 30°C and a cold reservoir held at 0°C. If you move 400 J of heat from the hot reservoir to the cold reservoir, what is the total change in entropy?
Answers
Answer:
Explanation:
Given the following :
Temperature (Th) of hot reservoir = 30°C (30 +273) = 303K
Temperature (Tc) of cold reservoir = 0°C (273K)
Quantity (Q) of heat transferred from hot reservoir = 400 J
Total change in entropy (ΔStotal) :
ΔStotal = ΔShot + ΔScold
ΔS = Q/T
Hot reservoir is losing 400J of heat ;
Q = - 400 J
ΔShot = Q/Th
ΔShot = - 400/303
ΔShot = - 1.32 J/K
ΔScold = Q/T
ΔScold = 400 / 273
ΔScold = 1.47 J/K
ΔStotal = ΔShot + ΔScold
ΔStotal = - 1.32 + 1.47
ΔS total = 0.15 J/K
Answer:
-400/303 = -1.32
400/273 = 1.47
-1.32 + 1.47 =
.15 J/K
Explanation:
a p e x
A rock is thrown at a window that is located 16.0 m above the ground. The rock is thrown from the ground at an angle of 40.0° above horizontal with an initial speed of 30.0 m/s and experiences no appreciable air resistance. If the rock strikes the window on its upward trajectory, from what horizontal distance from the window was it released?
Answers
Answer:
x = 27.3 m
Explanation:
This is a projectile launching exercise, let's start by looking for the time it takes for the rock to reach the height of the window.
Let's use trigonometry to find the velocities of the rock
sin 40 = [tex]v_{oy}[/tex] / v
cos 40 = v₀ₓ / v
v_{oy}= v sin 40
v₀ₓ = v cos 40
v_{oy} = 30 sin 40 = 19.28 m / s
v₀ₓ = v cos 40
v₀ₓ = 30 cos 40 = 22.98 m / s
we look for the time
[tex]v_{y}^2[/tex] = v_{oy}^2 - 2 g y
v_{y}^2 = 19.28 2 - 2 9.8 16 = 371.71 - 313.6 = 58.118
v_{y} = 7.623 m / s
we calculate the time
v_{y} = v_{oy} - gt
t = (v_{oy} - v_{y}) / g
t = (19.28 -7.623) / 9.8
t = 1,189 s
since the time is the same for both movements let's use this time to find the horizontal distance
x = v₀ₓ t
x = 22.98 1,189
x = 27.3 m
Suppose that you have been chosen for a space mission to a distant planet. Due to the length of time you'll be away from Earth you must carry out physical activity every day. On earth your, strength and conditioning trainer has determined you must do 90 minutes of exercise every day. If the vehicle is travelling at 0.80 c how much time, according to a timer on the space vehicle should you be active to meet your physical activity requirement?
Answers
Answer:
I should be active for 15 hours to meet the physical activity requirement.
Explanation:
Since time dilates in moving objects, we use the formula t = t₀/√(1 - β²) where t = time in space vehicle, t₀ = time on earth = 9 hours and β = v/c where v = speed of space vehicle = 0.8c.
So, t = t₀/√(1 - β²)
t = 9/√(1 - (v/c)²)
= 9/√(1 - (0.8c/c)²)
= 9/√(1 - (0.8)²)
= 9/√(1 - (0.64)
= 9/√0.36
= 9/0.6
= 15 hr
So, according to a timer on the space vehicle, I should be active for 15 hours to meet the physical activity requirement.
A bicycle has a momentum of 36 kg • m/s and a velocity of 4 m/s. What is the mass of the bicycle? 9 kg 32 kg 40 kg 144 kg
Answers
Answer:
9 kg
Explanation:
Momentum is mass times velocity.
p = mv
36 kgm/s = m (4 m/s)
m = 9 kg
The mass of the bicycle is 9 kg.
Momentum of the bicycle
The momentum of the bicycle is the product of mass and velocity of the bicycle.
P = mv
where;
P is momentumm is mass v is velocitym = P/v
m = 36/4
m = 9 kg
Thus, the mass of the bicycle is 9 kg.
Learn more about momentum here: https://brainly.com/question/7538238
You are the driver of the car in the photos above. You Are traveling at 30 mph when suddenly the car goes from its position in the first photo to the position in the second photo. What is happening
Answers
Answer:
the car uses teleportation, to zip to one side of the photo, to the other
Explanation:
solve for x, x=2.7(35)+1/2(-9.7)*35^2
Answers
The answer is:
-5846.75
A model rocket blasts off from the ground, rising straight upward with a constant acceleration that has a magnitude of 76.8 m/s2 for 1.99 seconds, at which point its fuel abruptly runs out. Air resistance has no effect on its flight. What maximum altitude (above the ground) will the rocket reach?
Answers
Answer:
Explanation:
Take note that when the fuel of the rocket is consumed, the acceleration would be zero. However, at this phase the rocket would still be moving up until all the forces of gravity would dominate and change the direction of the rocket. Hence, there will be a need to calculate two distances, one from the ground until the point where the fuel is consumed and from that point to the point where the gravity would change the direction.
Given:
a = 76.8 m/s^2
t = 1.99 s
Solution:
d = vi (t) + 0.5 (a) (t^2)
d = (0) (1.99) + 0.5 (76.8) (1.99)^2
d = 0+38.4×3.9601
d = 152.068m
vf = vi + at
vf = 0 + 76.8 (1.99)
vf = 152.83 m/s (velocity when the fuel is consumed completely)
Then, we calculate the time it takes until it reaches the maximum height.
vf = vi + at
0 = 152.83+(-9.8) (t)
0 = 152.83 + (-9.8) (t)
-152.83 = -9.8t
t = 152.83/9.8 s
t = 15.59s
Then, the second distance
d= vi (t) + 0.5 (a) (t^2)
d = 152.83 (15.59) + 0.5 (-9.8) (15.59^2)
d = 2382.6197- 1190.93
d = 1191.68m
Then, we determine the maximum altitude:
d1 + d2 = 152.068 m + 1191.68m = 1343.748m
If you look at faint stars, you can see them more easily on the edges of your vision than if you try to look directly at them. Why is this true?
Answers
Answer:
The retina comprises of rod and cone cells . The rod cells are responsible for black and white vision and require low light levels while the cone cells are responsible for color vision and require good/high light levels for better functioning.
When faint stars are looked at on the edges of the vision it allows more light from faint objects to strike the rod cells which then becomes more visible.
Six members of a synchronized swim team wear earplugs to protect themselves against water pressure at depths, but they can still hear the music and perform the combinations in the water perfectly. One day, they were asked to leave the pool so the dive team could practice a few dives, and they tried to practice on a mat, but seemed to have a lot more difficulty. Why might this be
Answers
Answer:
The sound travels differently in different medium according the density of the medium.
Explanation:
The sound travels faster in dense medium and can be heard by the vibration of the bone present in the ear. The ear plugs reduce the sound intensity in both medium water and on land (air).
In air the sound is not heard properly due to the earplugs that stops the as the vibration are not able to produce as sound is not able to reach to middle ear, but Navy researchers have discovered that sound under water is heard by the bone present behind the ear, vibrations mastoid.
Describe what happens to water waves when they strike a flat surface?
Answers
Answer:
In this case reflection occurs.
Explanation:
This happens when they bounce on objects that they can not pass through.
Hope it helps
okay.
what is the best defintion of efficency
Answers
Answer: Efficiency signifies a peak level of performance that uses the least amount of inputs to achieve the highest amount of output.
Explanation: It minimizes the waste of resources such as physical materials, energy, and time while accomplishing the desired output.
Answer:
The efficiency of a simple machine is defined as the ratio of useful work done by the machine ( output work) to the total work out into the machine ( input work).
Explanation:
EfficiencyIf a machine overcomes a load ' L ' and the distance travelled by the load is 'Ld' , the work done by the load is L× LD. It is also called output work or useful work.
Therefore, [tex] \boxed{Output \: work \: = L \: \times \: Ld}[/tex]
Likewise, The effort applied to overcome the load is 'E' and the distance covered by effort is 'Ed' , the work done by effort is E × Ed. It is also called input work.
Therefore, [tex] \boxed{Input \: work = E \times Ed}[/tex]
The efficiency of a simple machine is defined as the ratio of output work to the input work .
Therefore, [tex] \boxed{Efficiency ( η)= \frac{outpt \: work}{input \: work} \times 100\%}[/tex]
Efficiency is expressed in percentage. It is a ratio of two works. A machine is never 100% efficient. It is because no machine is friction free and due to friction, some of the input energy is wastes in the form of heat energy.
[tex] \mathrm{Hope \: I \: helped!}[/tex]
[tex] \mathrm{Best \: regards!}[/tex]
A train travels southwest from point A to point B through the Arizona desert at 55 mi/h. How far will the train travel six-and-a-half hours?
Answers
Answer:
357.5 miles
Explanation:
distance = speed × time
distance = (55 mi/h) × 6.5 h = 357.5 mi
The train will travel 357.5 miles in 6.5 hours.
At what altitude the value of ‘g’ would become one fourth (¼)of the surface of the earth?
Answers
Answer:
Explanation:
For acceleration due to gravity g , the expression is
g = GM / R² , where G is gravitational constant M is mass of the earth and R is radius of the earth .
At height h , let the value of it becomes g / 4 , so
g / 4 = GM / ( R + h )²
dividing
4 = [( R+ h)² / R² ]
2 = (R + h) / R
2 = 1 + h / R
h / R = 1
h = R
So at height equal to radius of the earth , acceleration due to gravity becomes 1 /4 of value on the surface of the earth .
A space rocket accelerates uniformly from rest to 160ms^-1 upwards in 4.0s, then travels with a constant speed of 160ms^-1 for the next 5.0s.
What is the initial acceleration of the rocket?
Answers
Answer:
40 ms¯².
Explanation:
To solve this problem, we shall illustrate the question with a diagram.
The attached photo gives a better understanding of the question.
From the attached photo:
Velocity (v) = 160 ms¯¹
Time (t) = 4 secs.
Acceleration (a) =?
Acceleration (a) = Velocity (v) /time (t)
a = v/t
a = 160/4
a = 40 ms¯²
Therefore, the initial acceleration of the rocket is 40 ms¯².
It takes Serina 1.72 hours to drive to school. Her route is 47 km long. What is Serina's average speed on her drive to school? Your Answer :
Answers
Explanation:
Average speed = distance / time
v_avg = 47 km / 1.72 hr
v_avg = 27.3 km/hr
A group of air particles in a balloon are spread far apart and moving rapidly around inside the balloon. The balloon is placed in a refrigerator for 30 minutes. What would you expect to happen to the appearance of the balloon? Explain your answer in terms of particle movement and their change in temperature. The balloon is removed from the refrigerator and placed on the kitchen counter. What would you expect to happen to the appearance of the balloon? Explain your answer in terms of particle movement and their change in temperature.
Answers
Answer:
1) The balloon will shrink
2) The balloon will grow bigger and regain its shape
Explanation:
By the kinetic theory of gases, we have;
[tex]v_{rms} = \sqrt{\dfrac{3 \cdot R \cdot T}{MW} }[/tex]
[tex]P = \dfrac{n \cdot MW \cdot vrms^2}{3 \cdot V}[/tex]
Where;
[tex]v_{rms}[/tex] = RMS Speed
R = The universal gas constant
T = The temperature
MW = The Molecular weight
n = The number of moles
V = The volume
P = The pressure
1) When the balloon is placed in the refrigerator for minutes, the temperature inside the balloon will drop and RMS speed will reduce, however due to the elastic wall of the balloon, the pressure will remain the same therefore the volume will reduce and the balloon will shrink
2) When the balloon is placed on the kitchen counter, the temperature inside the balloon will rise leading to the increase in the RMS speed which will raise the pressure effect on the wall of the balloon as the balloon is made of elastic material, as the pressure rises, the wall expands to keep the pressure constant and the volume occupied by the air particles will increase, the balloon will grow bigger and regain its shape.
What is the observation and what is the inference in the following text. Explain.
The chimpanzee climbed the tall tree. The chimpanzee must be very strong,
Answers
Observation: The chimpanzee climbed the tall tree.
Inference: The chimpanzee must be very strong,
Explanation:
An inference differs from an observation because an inference is a guess or possible explanation about a phenomenon. On the other hand, an observation is a statement based on evidence gathered through the senses. In this context, the sentence that is an observation is "The chimpanzee climbed the tall tree" because this statement is based on visual evidence. Moreover, the inference is "The chimpanzee must be very strong" because this is just a guess to explain how the chimpanzee climbed up the tree.
How has the games changed over the years?
Answers
Answer:
The definition of the particular circumstance consists provided in the subsection on the interpretation elsewhere here.
Explanation:
Throughout the past 10-20 years, the computer games industry is experiencing some insane shifts. Several of the adjustments are responsible for the observed market developments, while others are related to just the tech boom as well as technological development across the global economy. Here is another glimpse at some instances of how and why the gaming industry has evolved in just the last few decades.Matter must have two physical properties 1. Have mass, and 2
∆ Must move
∆ Use energy
∆ Take up space
∆ Be measure
able
Answers
Answer:
Take up space
Explanation:
Actually we know this by the definition of matter which states that "matter is any substance that has mass and takes up space by having volume."
hope it helped you:)
Help!!! Line B touches the circle at a single point. Line A extends through the center of the circle.
I. What is line b in reference to the circle?
2. How large is the angle between lines A and B?
Answers
Answer:
If I understand correctly. Line B is parallel to the circle. Also, the angle is less than 90.
The size of the circle determines. The diameter should not be fixed either.'Circle' is characterized as "a two-dimensional geometric figure comprising of the set of all those points in a plane that are at equal distance from the center."
1). Line B would be considered as the 'tangent' in association with the given circle.
2). The angle lying among the lines A and B would be of 90° i.e. right angle.
Given that,
A circle with line A drawn through its center
Line B moves while touching the edge of the circle and intersects line A outside the circle.
Since 'Tangent' is described as a 'straight-line touching the curve at one point without crossing it,' thus, line B would be considered as the tangent of the circle as it touches the circle's curve once. The angle that is formed at the intersection of the line A and B at the curve of the circle would be a right angle because they are perpendicular to one another. Thus, the perpendicular lines A and B form an angle of 90°.Learn more about 'circle' here:
brainly.com/question/11833983
if a direction is somewhere between North and East it is measured in _____?
Answers
Answer:
degrees
Explanation:
If a direction is somewhere between north and east, it is measured in degrees.
This measurement will be possible thanks to the existence of geographical coordinates that are some 'imaginary lines' that help us find our location on the earth's surface. These lines are called latitude and longitude, both of which are measured in degrees.
It is like a sea battle game where you have to combine the rows and columns in order to identify where the targets are located. Geographic coordinates work the same way, you must combine the rows and columns of the planisphere to identify the locations of the planet. So the lines would be the latitudes and the columns the longitudes.
Ken received a 66 on his first math exam, which counted for 20% of his final grade; he now believes that he won't be able to pass the class. His conclusion best illustrates a pessimistic outlook. the fight-or-flight response. problem-focused coping. relative deprivation.
Answers
Answer:
His conclusion best illustrates a pessimistic outlook.
Explanation:
As seen in the question above, Ken got 20% of his final grade in the first test he did for this class, that is, there will be other tests that can provide him to reach the grade needed to pass the class. However, even if there are possibilities, he believes that he will not pass the class, he does not have a positive and optimistic view of his future in this class and is sure that he will fail. This negative view of the future is an example of a pessimistic outlook.
A 4-N object object swings on the end of a string as a simple pendulum. At the bottom of the swing, the tension in the string is 9 N. What is the magnitude of the centripetal acceleration of the object at the bottom of the swing? Give the answer as a function of the acceleration due to gravity, g.
Answers
Answer:
Explanation:
Given mg = 4N .
m = 4 / g
At the bottom of the swing let centripetal acceleration be a
T - mg = ma
9 - 4 = ma
5 = 4 a / g
a = 5g / 4
prove p=f/a science chapter pressure
Answers
Explanation:
Let 'F' be force acting perpendicularly, 'A' be the area and 'P' be the pressure exerted.
Then,
Pressure is directly proportional to the the force acting perpendicularly i.e.
P ∝ F ............. (i)
Pressure is inversely proportional to the area on which force acts i.e.
P ∝ 1/A ........... (ii)
Combining equations (i) and (ii),
P ∝ F/A
or, P = K × F/A [where K is a constant]
If F is 1N, A is 1m² and P is 1 N/m², then K is 1.
So, P = F/A proved...
