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.
derive an expression for resistivity of conductor of length l and area of cross section A
Answer
Resistivity R = K * L / A where resistivity is constant for material, L the length of the material and A the area of the material
K = R * A / L where R is the resistance of the material
Which of the following is an example of an endothermic reaction?
A. Respiration
B. Acid neutralization
C. Combustion
D. Photosynthesis
Answer:
D, photosynthesis
Explanation:
Bonds Quick Check
Metallic bonds are responsible for many properties of metals, such as conductivity. Why is this possible? (1 point)
A Metals have low electronegativity, so they are conductive because they pass charges easily.
Two metals bonded together are going to be more conductive than a metal bonded with a
nonmetal
C An attraction between a positive charge and a negative charge is created.
The bonds can shift because valence electrons are held loosely and move freely.
Answer: The bonds can shift because valence electrons are held loosely and move freely.
Explanation:
what is the shape of the line graph that shows the temperature change over time of the liquid before it starts to boil?
The line graph showing the temperature change over time of a liquid before it boils has an upward-sloping trend as heat is applied until it reaches its boiling point, with fluctuations due to heat transfer rate changes.
What is the heat transfer rate?Heat transfer rate refers to the amount of heat energy transferred per unit of time between two objects or substances that are at different temperatures. It is a measure of how quickly heat is transferred between two objects or substances and is influenced by factors such as the temperature difference between the objects, the thermal conductivity of the materials, the surface area in contact, and the type of heat transfer mechanism involved (conduction, convection, or radiation). Heat transfer rate is often expressed in units of watts or BTUs per unit of time (e.g., watts/second or BTUs/hour).
Here in the Question,
The shape of the line graph that shows the temperature change over time of the liquid before it starts to boil is generally an upward-sloping line. As heat is applied to the liquid, its temperature will increase gradually until it reaches its boiling point. The rate of temperature increase may not be constant, and there may be some fluctuations due to factors such as changes in the rate of heat transfer.
Therefore, the trend of the line graph will be upward-sloping until the liquid reaches its boiling point.
To learn more about the boiling point of water click:
https://brainly.com/question/30462611
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What is a hypothesis?
A. A piece of information gathered during an experiment
OB. A source that summarizes a primary source
O C. Something that a scientist intentionally changes during an
experiment
O D. An educated guess about the outcome of an experiment
Answer:
D!!!!!
Explanation:
A hypothesis is a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
Answer:
D. An educated guess about the outcome of an experiment.
Explanation:
Hypothesis is an educated guess about the outcome of an experiment.
Hope this helps ;) ❤❤❤
what is system? Define
Answer:
a system is a set of some things which helps the good happenings in ousr day to day life. It also helps the astrophysisists to find the planets with a system
To see if your results are reasonable, you can compare the final velocity of the stone as it falls down unwinding the wire from the pulley, to the velocity the stone would have if falling the same distance while unconnected to the pulley. What is the velocity of an untethered stone after falling 0.337 m from rest
Answer:
The velocity of the stone is 2.57 m/s.
Explanation:
Given that
Height = 0.337 m
We need to calculate the velocity of the stone
Using equation of motion
[tex]v^2-u^2=2gh[/tex]
Where, v = velocity of stone
u = initial velocity
g = acceleration due to gravity
h = height
Put the value into the formula
[tex]v^2-0=2\times9.8\times 0.337[/tex]
[tex]v=\sqrt{2\times9.8\times0.337}[/tex]
[tex]v=2.57\ m/s[/tex]
Hence, The velocity of the stone is 2.57 m/s.
Rajah 9 menunjukkan laluan bagi kuching Fun Run. Berapakah sesaran bagi pelari tersebut? Mula 2 km 6 km Tamat 10 km Rajah Diagram 9 O A.5 km O B.6 km O c. 10 km D. 18 km
Answer:
jsjfj heddifii ididofi idididi hdhdii iridium didi buff joid duruvdudi 7u
A ball with a mass of 0.5 kg is attached to one end of a light rod that is 0.5 m long. The other end of the rod is loosely pinned at a frictionless pivot. The rod is raised until it is vertical, with the ball above the pivot. The rod is released and the ball moves in a vertical circle. The tension in the rod as the ball moves through the bottom of the circle is closest to:
Answer:
The tension in the rod as the ball moves through the bottom circle is 9.8 N
Explanation:
When the ball is released from rest, the centripetal force equals the weight of the ball. So mv²/r = mg where m = mass of ball = 0.5 kg, v = speed of ball, r = radius of vertical circle = length of rod = 0.5 m and g = acceleration due to gravity = 9.8 m/s²
v = √gr = √9.8 m/s² × 0.5 m = √4.9 = 2.21 m/s
Now at the bottom of the circle T - mg = mv²/r where T = tension in the rod
T = m(g + v²/r)
= m(g + (√gr)²/r)
= m(g+ gr/r)
= m(g + g)
= 2mg
= 2 × 0.5 kg × 9.8 m/s²
= 9.8 N
So, the tension in the rod as the ball moves through the bottom circle is 9.8 N
1 point
40 The diagram below shows an electrical circuit made up of a cell and three loads. The
voltage established by the cell and the resistance of each load is marked on the
diagram. Select the current flowing through the 3-ohm load.
www
1 ohm
12V
2 ohms
WWW
3 ohms
www
A. 4 amps
B. 2 amps
C. 5 amps
D. 0.25 amps
SPS106 DOK 3
Answer:
Option B. 2 A.
Explanation:
The following data were obtained from the question:
Resistance 1 (R1) = 1 Ω
Resistance 2 (R2) = 2 Ω
Resistance 3 (R3) = 3 Ω
Potential difference (V) = 12 V.
Current through the 3 Ω (I3) =?
Next, we shall determine the total resistance of the circuit.
This can be obtained as follow:
Resistance 1 (R1) = 1 Ω
Resistance 2 (R2) = 2 Ω
Resistance 3 (R3) = 3 Ω
Total resistance (R) =.?
R = R1 + R2 + R3
R = 1 + 2 + 3
R = 6 Ω
Next, we shall determine the current flowing in the circuit.
This can be obtained as follow:
From ohm's law,
Voltage (V) = current (I) x resistance (R)
V = IR
Potential difference (V) = 12 V.
Resistance (R) = 6 Ω
Current (I) =?
V = IR
12 = I x 6
Divide both side by 6
I = 12/6
I = 2 A.
Since the circuit is in series connection, therefore, the same current will flow through each resistor.
Therefore, the current through the the 3 Ω load is 2 A.
Answer answer answer it it it
Answer:
(B) Parachutes
Explanation:
Air resistance works to slow down trains and airplanes, so it isn't desirable. Air resistance also causes pendulums to slow and stop.
Parachutes need air resistance to slow a person's fall. So air resistance is desirable here.
Answer:
B i answered it it it
Explanation:
what does grit mean in psychology
Answer:
The meaning of grit in psychology is a positive, non-cognitive trait based on an individual's perseverance of effort combined with the passion for a particular long-term goal or end state.
What is one Pascal pressure? What is its unit?
Explanation:
the force acting perpendicularly on unit area of surface
unit=pascle .
A pressure of one Newton per square meter .. The SI unit of 1 Pascal pressure is 1 Newton per square metre .
Joseph jogs from one end A to the other end B of a straight 300 m road in 2 minutes 30 seconds and then turns around and jogs 100 m back to point C in another 1 minute. What are Joseph's average speeds and velocities in jogging (a) from A to B and (b) from A to C?
Answer:
Explanation:
(a) It is given that Joseph jogs on a straight road of 300m in a time interval of 2 minutes and 30 seconds, which is equal to 150seconds. Therefore, when Joseph jogs from point A to point B, he covers a distance of 300m in time of 150seconds. Hence, his average speed is 300m/150s=2ms^−1. Since it is a straight road and he jogs in a single direction in this case, his displacement is equal to 300m. Since it is a straight road and he jogs in a single direction in this case, his displacement is equal to 300m.
Hence, his average velocity is 300m/150s=2ms^−1
(b) Then it is given that he turns back and points B and jogs on the same road but in the opposite direction for a time interval for 1 minute and covers a distance of 100m.If we consider the whole motion of Joseph, i.e. from point A to point C, then he covers a total distance of 300m+100m=400m. And he covers this total distance in a time interval of 2.5min+1min=3.5min=210s.
Therefore, his average speed for this journey is 400m210s=1.9ms−1.
For the same journey is displacement is equal to the distance between the points A and C,i.e. 300m−100m=200m.
Hence, his average velocity for this case is 200m/210s=0.95ms^−1
"For a first order instrument with a sensitivity of .4 mV/K and a time" constant of 25 ms, find the instrument’s response as a function of time for a sudden temperature increase from 273 K to 473 K. Before the temperature increase, the instrument output was a steady 109.2 mV. Plot the response y(t) as a function of time. What are the units for y(t)? Find the 90% rise time for y(t90) and the error fraction, Γ(t90).
Answer:
Explanation:
Given that:
For a first order instrument with a sensitivity of .4 mV/K
constant c = 25 ms = 25 × 10⁻³ s
The initial temperature [tex]T_1[/tex] = 273 K
The final temperature [tex]T_2[/tex] = 473 K
The initial volume = 0.4 mV/K × 273 K = 109.2 V
The final volume = 0.4 mV/K × 473 K = 189.2 V
the instrument’s response as a function of time for a sudden temperature increase can be computed as follows:
Let consider y to be the function of time i.e y(t).
So;
y(t) = 109.2 + (189.2 - 109.2)( 1 - [tex]\mathbf{e^{-t/c}}[/tex])mV
y(t) = (109.2 + 80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV
Plot the response y(t) as a function of time.
The plot of y(t) as a function of time can be seen in the diagram attached below.
What are the units for y(t)?
The unit for y(t) is mV.
Find the 90% rise time for y(t90) and the error fraction,
The 90% rise time for y(t90) is as follows:
Initially 90% of 189.2 mV = 0.9 × 189.2 mV
= 170.28 mV
170.28 mV = (109.2 + 80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV
170.28 mV - 109.2 mV = 80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV
61.08 mV = 80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV
0.7635 mV = ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV
t = 1.44 × 25 × 10⁻³ s
t = 0.036 s
t = 36 ms
The error fraction = [tex]\dfrac{189.2-170.28 }{189.2}[/tex]
The error fraction = 0.1
The error fraction = 10%
The distance covered by a body along the x axis is given by x=2t^3+5t^2+t where t is measured in seconds and x is in meter. Find average speed in a time interval from t= 0s and t=2s
Explanation:
It is given that,
The distance covered by a body along the x-axis is given by :
[tex]x=2t^3+5t^2+t[/tex]
t is in seconds and x is meters
Speed of the body is given by :
[tex]v=\dfrac{dx}{dt}\\\\v=\dfrac{d(2t^3+5t^2+t)}{dt}\\\\v=6t^2+10t+1[/tex]
At t = 0,
[tex]v=6(0)^2+10(0)+1=1\ m/s[/tex]
At t = 2 s,
[tex]v=6(2)^2+10(2)+1=45\ m/s[/tex]
So, the average speed in a time interval from t= 0s and t=2s is 45 m/s.
how do you find average velocity
Answer:
find the sum of the inital and final velocitys and divide by 2 to find the average
-
Speed is a scalar, a quantity that is
described by
alone.
Answer:
True
Explanation:
Thats is true since it cannot be a vector because speed only gives a magnitude, not a direction as well.
Find the odd one out a)Planets moving on it's axis,Strings of guitar (being played),Motion of a ferry wheel,The vehicles moving on a straight road. b)Motion of the moon around the earth,Motion of the earth around the sun,Motion of a merry-go-round,Heart-beat in a healthy person. c)Motion of a bullet fired from gun,Motion of a football player in the ground,Motion of a vehicle on a straight road,Motion of an apple falling from a tree
Answer:
a) Strings of guitar (being played)
b) Heart-beat in a healthy person
c) Motion of an apple falling from a tree
Explanation:
a) The motion of the string of a guitar being played is the only motion involving simple harmonic motion.
b) All the other motions are circular motion except the heart beat in a healthy person, which is periodic.
c) The motion of an apply falling from a tree is the only motion under the complete influence of gravity from the onset till the end.
A baseball pitcher throws a 0.14 kg ball toward a batter who is 18 m away.
The ball is traveling at 40 m/s when it leaves the pitcher's hand. What is the
ball's kinetic energy at this point?
A. 112 J
OB. 224 J
C. 12J
D. 3 J
SUBMIT
Answer:
A. 112 J
Explanation:
KE = ½mv² = ½(0.14)40² = 112 J
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?
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
An American traveler in Kenya carries a transformer to convert Kenya's standard 240 V to 120 V so that she can use some small appliances on her trip. (a) What is the ratio of turns in the primary and secondary coils of her transformer? Np Ns = (b) What is the ratio of input to output current? Iin Iout = (c) How could a Kenyan traveling in the United States use this same transformer to power her 240 V appliances from 120 V?
Answer:
a) [tex]N_{p}[/tex]/[tex]N_{s}[/tex] = 2
b) [tex]I_{in}[/tex]/[tex]I_{out}[/tex] = 0.5
c) A Kenyan travelling in the united states will now use the output terminal of the transformer in Kenya as the input terminal in the United States, to step up the voltage from 120 V to 240 V for his devices
Explanation:
Kenya's standard voltage [tex]V_{p}[/tex] = 240 V
America's standard voltage [tex]V_{s}[/tex] = 120
using the transformer relationship
[tex]V_{p}[/tex]/[tex]V_{s}[/tex] = [tex]N_{p}[/tex]/[tex]N_{s}[/tex]
substituting values, we have
240/120 = [tex]N_{p}[/tex]/[tex]N_{s}[/tex]
[tex]N_{p}[/tex]/[tex]N_{s}[/tex] = 2
b) The power input must be equal to the power output
[tex]I_{in}[/tex][tex]V_{in}[/tex] = [tex]I_{out}[/tex][tex]V_{out}[/tex]
where [tex]I_{in}[/tex] = input current
[tex]V_{in}[/tex] = input voltage = 240 V
[tex]I_{out}[/tex] = output current
[tex]V_{out}[/tex] = output voltage = 120 V
Transposing the above equation, we get
[tex]I_{in}[/tex]/[tex]I_{out}[/tex] = [tex]V_{out}[/tex]/[tex]V_{in}[/tex]
[tex]I_{in}[/tex]/[tex]I_{out}[/tex] = 120/240 = 0.5
c) A Kenyan travelling in the united states will now use the output terminal of the transformer in Kenya as the input terminal in the United States, to step up the voltage from 120 V to 240 V for his devices.
An electric field from a charge has a magnitude of 4.5 x 10^4 N/C at a certain
location that points outward. If another charge with a magnitude of -2.0 x 10^-6 C
is brought near it, what is the strength of the electrostatic force that acts on this
charge and how do the two charges behave?
0.09 N; repel each other
-0.09 N; attract each other
-2.3 N; repel each other
2.3 N; attract each other
Answer:
4.5 x 10^4 x -2 x 10^-6 = -0.09N
Explanation:
-0.09N
select the correct relationship of the densities of the given substances: !●water < iron < aluminium < mercury ● Iron < water < mercury < aluminium ● water < aluminium < iron < mercury ● none of the above. asap plz!!!
Answer:
option a is correct
Explanation:
water ∠iron∠aluminium∠mercury
water density =1.0000
iron =7.487
aluminium=2.07
mercury=13.59
the scientist who gives the definition of work
Answer:
Work, in physics, measure of energy transfer that occurs when an object is moved over a distance by an external force at least part of which is applied in the direction of the displacement. ... To express this concept mathematically, the work W is equal to the force f times the distance d, or W = fd.
observe the virual skateboarder coming down the hill and over the ramp describe how each of newton’s laws of motion can be observed in this action you can choose the dry wet or muddy conditions or some combination of these
Answer:
first part the skater goes down a constant slope ramp, initially he has Newton's second law
pply Newton's third law, the normal is the reaction to the support of the body on the surface
the ramp shoots off. axis becomes zero and therefore with Newton's first law its speed
Explanation:
It is the description of this movement let's write Newton's laws.
* The first law that a body goes at constant speed or zero if the sum of the external forces is zero
* the second law is F = m a
* The third law states that the forces act in pairs of equal magnitude and opposite direction, one applied to each body.
Let's apply these laws to our case
In the first part the skater goes down a constant slope ramp, initially he has Newton's second law when he accelerates from the initial velocity of zero to a terminal velocity.
The expression for this is
Wₓ - fr = ma
W sin θ - μ W cos θ = m a
W = mg
g (sin θ - μ cos) = a
the value of the coefficient of kinetic friction depends on the condition of the surface, dry, wet or muddy
This is Newton's second law
On the Y axis, which is perpendicular to the ramp we have
N- [tex]W_{y}[/tex] = 0
If we apply Newton's third law, the normal is the reaction to the support of the body on the surface, note that it can be different from the weight.
In the second part when he is on the ramp.
In the ramp the skater enters with a speed v, suppose that the ramp has an incline so that the skater can jump, in this case the angle is positive with respect to the axis x
In this case the analysis is similar to the previous one
Newton's second law gives the acceleration of the skater, who when he reaches the end of the ramp shoots off.
At this point the force in the x (horizontal) axis becomes zero and therefore with Newton's first law its speed this axis remains constant and the force in the y axis is the force of gravity and has an acceleration that changes if velocity according to Newton's second law
Answer:look at explanations
Explanation:
A car travels from point A to B in 3 hours and returns back to point A in 5 hours. Points A and B are 150 miles apart along a straight highway. Which of the following statements most accurately describes the motion of the car? Choose 1 answer:(Choice A) A The average velocity is 40 miles per hour. (Choice B) B The total displacement of the trip is 300 miles. (Choice C) C The average speed is 37.5 miles per hour. (Choice D) D The car travels at 50 mph for the first half and 30 mph for the second half.
Answer: D
Explanation:
Given that a car travels from point A to B in 3 hours and returns back to point A in 5 hours. Points A and B are 150 miles apart along a straight highway.
From point A to B
The speed = distance / time
Where
Distance = 150 mile
Time = 3 hours
Substitute the values into the formula
Speed = 150/3 = 50 mile/ hours
From Point B to Point A
Distance = 150 miles
Time = 5 hours
Where speed = distance/ time
substitute all the parameters into the formula
Speed = 150/5 = 30 mph
Therefore, The car travels at 50 mph for the first half and 30 mph for the second half.
The correct answer is option D
Một xe chạy trong 2 giờ với tốc độ trung bình 45 km/h rồi chạy tiếp 4 giờ với tốc độ trung bình 40 km/h. Tốc độ trung bình của xe trong cả quá trình chuyển động đó gần giá trị nào nhất sau đây?
Answer:
hlo
Explanation:
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An average skater averages 11 m/s over the first 5 seconds of a race. find the average speed required over next 10 seconds to average 12 m/s overall.
Answer:
usa
Explanation:
3 bulbs are in series and the same 3 bulbs are in parallel with the same battery. Which bulbs will be dimmer?
A. The same
B. Parallel
C. Series
D. Not enough info
Answer:
Explanation:
The series three. The series 3 will cut the voltage into 1/3. The current will also be lower because of the voltage drop.
The parallel circuit will not cut the voltage and the current will be tripled because each bulb is taking out exactly what it needs.
As an aside, house wiring would be a nightmare if the bulbs were connected in series. If one bulb burned out, you'd have to find it in the dark because they all would go out.