Answer:
am I the only one seeing blink
5. Tại sao khi lặn ta luôn cảm thấy tức ngực và càng lặn sâu thì cảm giác tức ngực càng tăng? A. Ap suất của nước giảm B. Ap suất không khí tăng C. Ap suất không khí giảm D. Ap suất của nước tăng
Answer:
c and d
Explanation:
obviously kksxsxksxkskxkskxksxksxsxsxsxsxsxsxs
How does the electric field intensity vary with the increase of distance of the point from the centre of a charged conducting sphere? Explain with graph.
Answer:
(i) Electric field outside the shell:
For point r>R; draw a spherical gaussian surface of radius r.
Using gauss law, ∮E.ds=q0qend
Since E is perpendicular to gaussian surface, angle betwee E is 0.
Also E being constant, can be taken out of integral.
So, E(4πr2)=q0q
So, E=4πε01r2q
_____ of cylindrical vessel
avoids the transfer
of heat into or out of
the calorimeter.
Answer:
Insulation.
Explanation:
A calorimeter can be defined as a scientific instrument or device designed and developed for measuring the heat involved in reactions or other processes, especially by taking the measurement of the temperature of the materials surrounding the process.
Basically, a calorimeter is insulated using materials with very high level of resistivity so as to prevent heat transfer to the outside of the device (calorimeter).
This ultimately implies that, insulation of cylindrical vessel prevents the transfer of heat into or out of the calorimeter.
What did Ernest Rutherford's experiment of a beam of alpha particles aimed
at a sheet of gold foil lead him to conclude?
A. The theory that atoms were the building block of all matter was
correct.
B. The majority of the atom's mass and its positive charge are
concentrated in the atom's center.
C. An electron has a larger mass than the alpha particles, causing
them to reflect upon collision.
D. J.J. Thomson's theory of electrons suspended in a sea of
positively charged particles was correct.
Answer:
B - Only a concentration of mass in the nucleus could explain the deflection of the incident particles.
A compound eye __________. ANSWER Unselected is composed of thousands of prisms that focus light onto only a few photoreceptor cells Unselected All of the listed responses are correct. Unselected works best for resolving stationary images Unselected contains many individual light detectors, each with its own lens Unselected is possessed only by insect
Answer:
contains many individual light detectors, each with its own lens
Explanation:
The compound eye is found mainly in insects and crustaceans, it is composed of individual receptor units, each with its focus, sensing nerve; each one gives a small image of the environment, so the image is mosaic type, not a complete integral image of the environment.
When reviewing the different statements, the correct one is
contains many individual light detectors, each with its own lens
a skydiver of mass 80kg jumpes from a plane. Taking g=m/s^2 write down the weight of skydiver
Answer:
800N
Explanation:
as we know that
weight = mass × acceleration due to gravity
= 80kg × 10 m/s^2
= 800N.
why do the other animals listen to old major speak in the barn late on night?
balance the following equations: CUCO3+H2SO4- CUSO4+H2O+CO2
Answer:
It is already balanced
Explanation:
It is already balanced
Calculate the relative atomic mass of MgO
Answer:
MgO relative atomic mass is 40
Explanation:
Mg=24
O=16
What type of sound do the thinner
strings on a guitar make?
A. Higher pitched sounds
B. Lower pitched sounds
C. Loud sounds
D. Quiet sounds
Answer:
d
Explanation:
I'm not perfectly sure so check again
A tray containing 0.20kg of water at 20degree celsius is placed in a freezer. The temperature of the water drops to 0degree celsius in 10 minutes. Calculate
a) The energy lost by the water asit cools to 0 degree celsius.
b) The average rate at which the water is losing energy in J/s.
c) Estimate the time taken for the water at 0 degree celsius to turn completely into ice.
d) state any assumptios you make
Answer:
a. Energy lost, Q = 16,800 Joules.
b. Power = 28 J/s
c. Time, t = 2357.14 seconds
d. I assumed that the ice remained at a temperature of zero degrees Celsius (0°C). Also, I assumed that the heat is being lost at a constant rate.
Explanation:
Given the following data;
Mass = 0.20 kgInitial temperature, T1 = 20°CFinal temperature = 0°CTime = 10 minutesa. To find the energy lost by the water as it cools to 0 degree celsius;
Mathematically, heat capacity is given by the formula;
[tex] Q = mcdt [/tex]
Where;
Q represents the heat capacity or quantity of heat.M represents the mass of an object.C represents the specific heat capacity of water.dt represents the change in temperature.dt = T2 - T1
dt = 20 - 0
dt = 20°C
We know that the specific heat capacity of water is equal to 4200 J/kg°C
Substituting the values into the formula, we have;
[tex] Q = 0.20 * 4200 * 20 [/tex]
Energy lost, Q = 16,800 Joules.
b. To find the average rate at which the water is losing energy in J/s by using the following formula;
[tex] Power = \frac {energy}{time} [/tex]
First of all, we would have to convert the value of time in minutes to seconds.
Conversion:
1 minute = 60 seconds
10 minutes = X seconds
Cross-multiplying, we have;
X = 60 * 10
X = 600 seconds
Substituting the values into the formula, we have;
[tex] Power = \frac {16800}{600} [/tex]
Power = 28 J/s
c. To estimate the time taken for the water at 0 degree celsius to turn completely into ice;
We know that the latent heat of fusion of water is equal to 3.3 * 10⁵ J/kg.
Mathematically, the latent heat of fusion is calculated by using the formula;
Energy, Q = ml = pt
Substituting the values into the formula, we have;
0.20 * 3.3 * 10⁵ = 28 * t
0.20 * 330000 = 28t
66000 = 28t
[tex] t = \frac {66000}{28} [/tex]
Time, t = 2357.14 seconds.
d. The assumption made is that, the ice remained at a temperature of zero degrees Celsius (0°C). Also, I assumed that the heat is being lost at a constant rate.
Draw a wave that has a wavelength of 3 cm and an amplitude of 1 cm. Label the wavelength, the amplitude, the rest position, and the crest and trough of your wave.
Answer:
Please find attached, the required wave drawn with MS Excel
Explanation:
Functions that represent waves is given as follows
A general form of the wave equation is A·sin(B·x) + D
Where;
B = 2·π/T
T = The period of the wave = 1/f
D = The vertical shift of the wave = 0
A = The amplitude of the wave = 1 for sine wave
v = The wave velocity
λ = The wavelength of the wave
f = The frequency of the wave
v = f·λ
At constant v, λ ∝ 1/f
∴ λ ∝ T
Where T = 3, we have;
B = 2·π/T
∴ B = 2·π/3
Therefore, we have the wave with an amplitude of 1 cm, and wavelength, 3 cm, given as follows
y = sin((2·π/3)·x)
Plotting the above wave with MS Excel, we can get the attached wave
If the half-life of a decaying isotope is 10 years, which statement is true after
10 years?
Answer:
no is the most expensive but u have
a bubble of gas rises to the surface of a soft drink. this is because
is noise energy a kind of energy or not
A 4000 N force acts on an object that initially has a momentum of 400 kg-m/s for 0.9 seconds. What is the final momentum of the system?
Answer:
4360 Kgm/s
Explanation:
Applying,
Ft = M-M'................. Equation 1
Where F = force, t = time, M = Final momentum, M' = Initial momentum.
make M the subject of the equation
M = Ft+M'............ Equation 2
From the question,
Given: F = 4000 N, t = 0.9 seconds, M' = 400 kg-m/s
Substitute these values into equation 2
M = 4000+(0.9×400)
M = 4000+360
M = 4360 kgm/s
Hence the final momentum is 4360 kgm/s
They want a mixture of 150 grams of water at 60 degrees Celsius, using hot water at 90 degrees Celsius and cold water at 14 degrees Celsius, how many grams of water should be used per face?
Answer:
Explanation:
Here,
Final mass(m)=150g
Final Temperature(t)=60°C
Temperature of hot water(t1)=90C
Temperature of cold water(t2)=14C
Let the grams of water to be used per face be m1 grams and (150-m1) grams for hot and cold water respectively.
We know that,
Heat lost by hot body=Heat gained by cold body
or, m1 s1 Δt1=m2 s2 Δt2
or, m1 (t1-t)=(150-m1) (t-t2) [∵s1=s2, SHC of water is taken to be same]
or, m1 (90-60)=(150-m1) (60-14)
or, 30m1=6900-46m1
or, 76m1=6900
∴m1=90.79g
(150-m1)=59.21g
Hence, 90.79g and 59.21 g hot and cold water must be used respectively.
6x+8=32 kết quả x là bao nhiêu
Answer:
6x+8=32
6x=32-8
6x=24
x=24:6
x= 4
vậy, x =4
Examine the motion map. One animal is an antelope that is already running. The other is a cheetah that starts running after the antelope passes it. Does A or B represent the motion of the cheetah?
Answer:
A although am not seeing the cheetah
use the particle model to explain why the water expands
Answer:
Take water as an example; the size, shape and chemical composition of the water particles remains the same whether it is solid water (ice) or gaseous water (steam) - but how those particles move and are arranged is different for
22. In an experiment to determine the density of a soil using a density bottle, the following measuren were recorded. Mass of empty density bottle = 42.9g Mass of density bottle full of water = 66.1g Mass of density bottle with some soil = 67.2g Mass of density bottle with soil filled up with water = 82.0g Use the above data to determine the a) Mass of water that completely filled the bottle (2 b) Volume of water that completely filled the bottle
Answer:1
Explanation:1
the atomic number of phosphorus is
Answer:
The atomic number of phosphorus is 15.
Explanation:
It’s found after Si(Silicon) and before S(sulphur)
Name the type of motion executed by the motion of the moon around the earth.
Answer:
The motion of the moon around the earth is circular motion
Explanation:
You observe that you see more mockingbirds in small trees and more hawks in large trees. Which of the following is an appropriate scientific question based on this observation?
How does the size of a tree affect the bird species that prefer to live in it?
How do birds fly?
What type of food do birds eat?
What time of year to birds mate?
Answer:
A) How the size of a tree affect the bird species that prefer to live in it
Explanation:
I took the quiz
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.
what is velocity give its SI unit
Answer:
Velocity is the speed of something given in a direction. the SI unit of velocity is metre per second or m/s.
which is not a common theory on how the effects of hypnosis occurs
Answer:
EFFECTS Adverse reactions to hypnosis are rare, but may include: Headache. Drowsiness. Dizziness
If 200 ml of tea at 90 °C is poured into a 400 g glass cup initially at 25 °C, what would be the final temperature of the mixture?
Note: The specific heat capacity of water is 4186 J/kg °C, and the specific heat capacity of glass is 840 J/kg °C.
The final temperature of the mixture is 43.62 °C, If 200 ml of tea at 90 °C is poured into a 400 g glass cup initially at 25 °C.
To solve the question above, we apply the law of calorimetry
The law of calorimetry: which states that if there is no lost of heat the surrounding, heat lost is equal to heat gained, or it can be stated as heat absorbed by a cold body is equal to heat released by a hot body, provided there is no lost of heat to the surrounding.
The law above is expressed mathematically as
[tex]Cm(T-t) = C'm'(t-T')[/tex]............. Equation 1
Using equation 1 to solve the question,
Let: C = specific heat capacity of glass cup, m = mass of glass cup, C' = specific heat capacity of tea, m' = mass of tea, T = initial temperature of tea, T' = initial temperature of glass cup, t = final temperature of the mixture.From the question,Given: m = 400 g = 0.4 kg, C = 840 J/kg°C, m' = 200g (tea is a liquid made of water and the volume of water in ml is thesame a its mass in gram) = 0.2 kg, C' = 4186 J/kg.°C, T = 90°C, T' = 25°CSubstitute these values into equation 1 and solve for t₃[tex]0.4(840)(90-t) = 0.2(4186)(t-25)[/tex]
[tex]336(90-t) = 837.2(t-25)[/tex]
[tex]30240-336t = 837.2t-20930[/tex]
collect like terms
[tex]837.2t + 336t = 30240+20930[/tex]
[tex]1173.2t = 51170[/tex]
[tex]t = 51170/1173.2[/tex]
[tex]t = 43.62[/tex] °C
Hence, the final temperature of the mixture is 43.62 °C
Learn more about calorimeter here: https://brainly.com/question/15479803
Answer:
The final temperature of the system is 41.657 °C.
Explanation:
Let consider the tea-cup system as an isolated system, that is, a system with no energy and mass interactions with the surroundings. From the perspective of the First Law of Thermodynamics, the tea releases heat, which is received by the glass cup until thermal equilibrium is reached. The following formula represents the model under assumption that process was at steady state:
[tex]\rho_{w}\cdot V\cdot c_{w}\cdot (T_{w,o}-T) + m_{g}\cdot c_{g}\cdot (T_{g,o}-T) = 0[/tex] (1)
Where:
[tex]\rho_{w}[/tex] - Density of water, in grams per mililiter.
[tex]V[/tex] - Volume of tea, in mililiters.
[tex]c_{w}[/tex] - Specific heat of water, in joules per gram-degree Celsius.
[tex]m_{g}[/tex] - Mass of the glass cup, in kilograms.
[tex]c_{g}[/tex] - Specific heat of the glass cup, in joules per gram-degree Celsius.
[tex]T_{w,o}[/tex] - Initial temperature of tea, in degrees Celsius.
[tex]T_{g,o}[/tex] - Initial temperature of the glass cup, in degrees Celsius.
[tex]T[/tex] - Final temperature of the tea-cup system, in degrees Celsius.
If we know that [tex]\rho_{w} = 1\,\frac{g}{mL}[/tex], [tex]V = 200\,mL[/tex], [tex]c_{w} = 4.186\,\frac{J}{g\cdot ^{\circ}C}[/tex], [tex]m_{g} = 400\,g[/tex], [tex]c_{g} = 0.840\,\frac{J}{g\cdot ^{\circ}C}[/tex], [tex]T_{w,o} = 90\,^{\circ}C[/tex] and [tex]T_{g,o} = 25\,^{\circ}C[/tex], then the final temperature of the tea-cup system is:
[tex]\rho_{w}\cdot V\cdot c_{w}\cdot (T_{w,o}-T) + m_{g}\cdot c_{g}\cdot (T_{g,o}-T) = 0[/tex]
[tex]\rho_{w}\cdot V\cdot c_{w}\cdot T_{w,o} +m_{g}\cdot c_{g}\cdot T_{g,o} - (\rho_{w}\cdot V\cdot c_{w}+m_{g}\cdot c_{g})\cdot T = 0[/tex]
[tex]T = \frac{\rho_{w}\cdot c_{w}\cdot T_{w,o}+m_{g}\cdot c_{g}\cdot T_{g,o}}{\rho_{w}\cdot V\cdot c_{w}+m_{g}\cdot c_{g}}[/tex]
[tex]T = \frac{\left(1\,\frac{g}{mL} \right)\cdot \left(4.186\,\frac{J}{kg\cdot ^{\circ}C} \right)\cdot (200\,mL)\cdot (90\,^{\circ}C)+(400\,g)\cdot \left(0.840\,\frac{J}{g\cdot ^{\circ}C} \right)\cdot (25\,^{\circ}C)}{\left(1\,\frac{g}{mL} \right)\cdot \left(4.186\,\frac{J}{kg\cdot ^{\circ}C} \right)\cdot (200\,mL) +(400\,g)\cdot \left(0.840\,\frac{J}{g\cdot ^{\circ}C} \right)}[/tex]
[tex]T = 41.657\,^{\circ}C[/tex]
The final temperature of the system is 41.657 °C.
Two solid cubes have the same Mass but their edges are in the ratio of 4:1. What isthe ratio of their densities?
Let m be the mass of both cubes. If the smaller cube has side length x, then its volume is x ³. The side lengths of the larger cube have length 4x, so the larger cube's volume is (4x)³ = 64x ³, or 64 times as large as the smaller cube.
The first cube has a density of m/x ³, while the larger one has a density of m/(64x ³) = 1/64 m/x ³, so the ratio of densities is (1/64):1, or 1:64 (larger cube to smaller cube).
Which of the following best describes reverberation?
A.The wave fronts become mixed and broken up due to contact with a rough or
irregular surface.
B. A change in the sound wave velocity causes the wave to bend in a different
direction.
C. A fraction of the sound waves are absorbed by an object and converted to heat
energy.
D. A single sound undergoes several reflections due to multiple reflecting surfaces.
Reverberation, in psychoacoustics and acoustics, is a persistence of sound after the sound is produced
Explanation:
I think it is right hope its helps
Answer:
D. A single sound undergoes several reflections due to multiple reflecting surfaces.
Explanation:
Sometimes, the source of a sound is surrounded by multiple reflecting surfaces. The waves traveling from the source strike these different surfaces, causing multiple reflections. For example, a single clap of thunder reflects on several clouds and the earth's surface, causing you to hear a rolling rumble instead of a single sound.
