A point source emits sound waves with a power output of 135 watts. What is the sound level (in dB) at a distance of 10 m
Answer:
The sound level of the point source at a distance of 10 meters is approximately 110.294 decibels.
Explanation:
First, we calculate the intensity ([tex]I[/tex]), in watts per square meter, by the Inverse-Square Law:
[tex]I= \frac{\dot W}{4\pi\cdot r^{2}}[/tex] (1)
Where:
[tex]\dot W[/tex] - Power, in watts.
[tex]r[/tex] - Radius, in meters.
And the sound intenity level ([tex]L[/tex]), in decibels, is expressed by:
[tex]L = 10\cdot \log_{10} \frac{I}{I_{o}}[/tex] (2)
Where [tex]I_{o}[/tex] is the reference sound intensity, in watts per square meter.
If we know that [tex]\dot W = 135\,W[/tex], [tex]r = 10\,m[/tex] and [tex]I_{o} = 10^{-12}\,\frac{W}{m^{2}}[/tex], then we find that sound level at a distance of 10 meters is:
[tex]I= \frac{\dot W}{4\pi\cdot r^{2}}[/tex]
[tex]I = 0.107\,\frac{W}{m^{2}}[/tex]
[tex]L = 10\cdot \log_{10} \frac{I}{I_{o}}[/tex]
[tex]L \approx 110.294\,dB[/tex]
The sound level of the point source at a distance of 10 meters is approximately 110.294 decibels.
A 20 g block of ice is cooled to −65 ◦C. It
is added to 570 g of water in an 76 g copper
calorimeter at a temperature of 26◦C.
Find the final temperature. The specific
heat of copper is 387 J/kg ·
◦C and of ice is
2090 J/kg ·
◦C . The latent heat of fusion of
water is 3.33 × 10^5
J/kg and its specific heat
is 4186 J/kg ·
◦C .
Answer in units of ◦C.
Answer:
The final temperature is approximately 23.55°C
Explanation:
The given parameters are;
The mass of the ice block, m₁ = 20 g
The initial temperature of the block, T₁ = -65°C
The mass of the water to which the block is added, m₂ = 570 g
The mass of the copper container containing the water, m₃ = 76 g
The initial temperature of the water and the copper, T₂ = 26°C
The specific heat capacity of copper, c₃ = 387 J/(kg·°C)
The specific heat capacity of ice, c₄ = 2,090 J/(kg·°C)
The latent heat of fusion of ice, l = 3.33 × 10⁵ J/kg
The specific heat capacity of water, c₁ = 4,186 J/(kg·°C)
We have;
ΔQ = m₁·c₁·ΔT + m₁·l = m₂·c₂·ΔT + m₃·c₃·ΔT
Therefore, we get;
20 × 2,090 × -65 + 20 × 3.33 × 10⁵ + 20 × T × 4,186 = 570 × 4,186 × (26 - T) + 76 × 387 × (26 - T)
Using a graphing calculator, we get;
83720·T + 3943000 = 62801232 - 2415432·T
The final temperature, T ≈ 23.55 °C
Look at the circuit diagram. A rectangular box of lines with the long horizontal side. The left side has a circle with an X in it. The top side from left has a small circle connected to another small circle by a horizontal line and then a circle with an X in it. The right side from the top has a small circle connected to another small circle by a horizontal line and then a circle with an X in it. The bottom side has a stack of vertical lines, which are from left short, very short, short, very short. What does the diagram show? one battery, two light bulbs, and three resistors one battery, two switches, and three light bulbs one switch, one resistor, and three light bulbs one switch, one light bulb, and three batteries
Answer:
it is b on edge not d, well atleast for me it was b
Explanation:
Answer:
B) one battery, two switches, and three light bulbs
Explanation:
HELP ME ASAP PLZ!
What is the relationship between an electromagnetic wave and the vibrations of the electric and magnetic fields it moves through.
A charge of +3.5 nC and a charge of +5.0 nC are separated by 40 cm. Find the equilibrium position for a -6.0 nC charge.
Answer: [tex]18.22\ cm[/tex] from [tex]3.5\ nC[/tex] charge.
Explanation:
Given
The magnitude of the first charge is [tex]Q_1=3.5\ nC[/tex]
The magnitude of the second charge is [tex]Q_2=5\ nC[/tex]
[tex]-6\ nC[/tex] charge must be placed in between the two charges to establish equilibrium
The electrostatic force is given by
[tex]F=\dfrac{kq_1q_2}{r^2}[/tex]
Equilibrium will be established when force by both the charges balance out each other. Suppose [tex]-6\ nC[/tex] is placed at a distance of [tex]x[/tex] cm from [tex]3.5\ nC[/tex] . So, we can write
[tex]\Rightarrow \dfrac{k(3.5)(-6)}{x^2}=\dfrac{k(5)(-6)}{(40-x)^2}[/tex]
Canceling similar terms
[tex]\Rightarrow \left [ \dfrac{40-x}{x}\right ]^2=\dfrac{10}{7}\\\\\Rightarrow \dfrac{40-x}{x}=\sqrt{\dfrac{10}{7}}=1.195\\\\\Rightarrow 40-x=1.195x\\\Rightarrow 40=2.195x\\\Rightarrow x=18.22\ cm[/tex]
Thus, the equilibrium position is [tex]18.22\ cm[/tex] from [tex]3.5\ nC[/tex] charge.
Answer:
What school do you go to?
Explanation:
How do you rationalize the tension being used in Tennis Racket strings using the concept of impulse and momentum?
Answer:
The momentum, ΔP, and therefore, kinetic energy given to the ball in a serve is the result of the product of the tension force, 'F', in the string and the time of contact, Δt, between the ball and the string
ΔP = F × Δt
Explanation:
The impulse, ΔP, is the produce of the force, 'F', applied to a body for a given period of time, Δt', that gives motion to the body, and it is equal to the change of momentum of the body
ΔP = F × Δt
The momentum, 'P', of a body is the product of the mass, 'm', of the body and its velocity, 'v'
P = m × v
Tension is the axial pulling force of a string
T = Axial Force, F[tex]_{axial}[/tex]
The tension used in Tennis Racket strings is between 40 to 65 lbs.
When high tension is used in the string, the string is taut, and the contact duration between the Racket string and the ball is minimal, and the player needs to use more force to obtain a high momentum, and therefore, energy in the ball, which reduces control, and increase stress, as force is more emphasized
When low tension is used in the string, the Tennis Racket strings are more elastic. During a serve, the ball pushes the strings further back into the racket, such that the ball spends more time in contact with the string, (Δt is larger), and therefore, the impulse, F·Δt = ΔP, given to the ball is larger, therefore, the ball has a larger change in momentum, and therefore more energy in the intended direction.
However, a very slackened string will increase the increase area and time (large Δt) of contact of the ball and the racket such that the force given to the ball, F = ΔP/(large Δt) is reduced and therefore reduce the likelihood of gaining points from a serve against an opponent with a much forceful return of a serve.
A 30 gram ball rolls along a flat surface at a constant speed in the same direction over 4 meters in 20 seconds. Which is the speed of the
ball? (speed = distance = time)
A. 0.2 meters per second
OB. 0.5 meters per second
c. 20 meters per second
D. 80 meters per second
Please answer this FAST!
What is the power of a circuit with voltage 12 V and current 8.0
A?
Answer:96 W
Explanation:
when do i know if the acceleration (a) in newtons second law is 0?
Answer:
When the sum of all forces applied to the object is 0.
Explanation:
N2L states that net force equals an object's mass times its acceleration (F = ma). If the net force is 0, the acceleration of the object is 0.
On the second note, when an object has 0 acceleration (which means it has a constant velocity), it is in equilibrium (N1L).
What happens to energy when it is consumed?
Answer:
It converts to other energy
HELPPP
A 1.50-kg cart rolls along a horizontal table at a constant speed of 1.70 m/s. A ball of soft putty is dropped from a stationary hand onto the cart as it passes underneath. If the speed of the cart is reduced to 1.53 m/s, calculate the mass of the ball of putty. This collision is completely inelastic
Answer:
0.17 kg
Explanation:
mc = mass of cart
mb = mass of ball
vc = speed of cart before collision
vb = speed of ball before collision (vb = 0)
v' = speed of cart and ball after collision
mc . vc + mb . vb = (mc + mb) . v'
(1.5)(1.7) + mb(0) = (1.5 + mb) . 1.53
2.55 + 0 = (1.5 + mb) . 1.53
2.55/1.53 = 1.5 + mb
5/3 = 3/2 + mb ( I change it to fraction)
mb = 5/3 - 3/2 = 10/6 - 9/6 = 1/6 kg
mb = 1/6 kg = 0.17 kg
If a girl carries groceries up a flight of stairs, is she doing work on the groceries? Explain.
Answer:
Explanation:
Yes she is doing work. With or without the groceries, she is still doing work. She does more work with the groceries than without because Work is defined by F which is defined by mass. The mass increases with the groceries.
The work done is against the force of gravity.
The semi-major axis of this ellipse is 8.8 cm, and the distance from one of the foci to the
center is 4.4 cm. What is the eccentricity of the ellipse?
The eccentricity is 0.5
why doesn't every planet have a moon?
Answer:
Up first are Mercury and Venus. Neither of them has a moon. Because Mercury is so close to the Sun and its gravity, it wouldn't be able to hold on to its own moon. Any moon would most likely crash into Mercury or maybe go into orbit around the Sun and eventually get pulled into it.
An RC circuit consists of a resistor with resistance 1.0 kΩ, a 120-V battery, and two capacitors, C1 and C2, with capacitances of 20.0 μF and 60.0 μF, respectively. Initially, the capacitors are uncharged; and the switch is closed at t = 0 s. How much charge will be stored in eah capacitor after a long time has elapsed (capacitor one 2.4 x 10^-3 C) (capacitor 2 7.2 x 10^-3 C) and what will the total charge on both capacitors two time constants after the switch is closed? (8.3 x 10^-3)
Answer:
[tex]Q_t= 8.3 * 10^3 C[/tex]
Explanation:
From the question we are told that:
Resistor [tex]R=1000ohms[/tex]
Voltage [tex]v=120_V[/tex]
Capacitance of c_1 [tex]c_1=20 \mu F[/tex]
Capacitance of c_2 [tex]c_2=60 \mu F[/tex]
Time [tex]t=0[/tex]
Generally the equation for charges is mathematically given by
[tex]For C_1\\Charge\ on\ C_1 = CV = 20*120 = 2400 μC = 2.4 x 10^-3 C\\Charge\ on\ C_1 = 2400 μC = 2.4 x 10^-3 C\\Charge\ on\ C_1 = 2.4 x 10^-3 C\\[/tex]
[tex]ForC_2\\Charge on C_2 = 60*120 =7200 μC = 7.2 x 10^-3\\Charge on C_2 = 7.2 x 10^-3[/tex]
Generally the equation for voltage across capacitors is mathematically given by
[tex]V_c(t)=V(1-e^{-t/RC})[/tex]
[tex]C=C_1+C_2=80 \mu f\\t=2RC=>160000s[/tex]
[tex]V_c(t)=120(1-e^{-(160000)/1000*(80)})[/tex]
[tex]V_c(t)=103.7598[/tex]
Generally the equation for charges is mathematically given by
[tex]Q1(t) = C1Vc(t)\\Q1(t) = 20*103.7598\\Q1(t) = 2075.196\\\\Q2(t) = 60*103.7598\\Q2(t) = 6225.6\\[/tex]
Generally the equation for total charges [tex]Q_t[/tex] is mathematically given by
[tex]Q_t=Q1(t)+Q2(t)[/tex]
[tex]Q_t= 8.3 * 10^3 C[/tex]
If a car moves 12 km north, 19 km east, and 12 km south, what is its displacement?
Answer:
19 km.
..............
Explanation:
.....
Answer:The Distance is 43 and displacement is 5km south
Explanation: To find the distance you add up all the numbers which was 43 and to fine the displacement subtract all the numbers and since all the other numbers were out expect for -5 which was south you would put 5 km south , if the number has a negative on it , it doesnt matter.
PLEASE HELP !!!
Which statement correctly describes protons?
A.
They have no charge and are present in the nucleus of an atom.
B.
They have a negative charge and travel around the nucleus of an atom.
C.
They have a positive charge and travel around the nucleus of an atom.
D.
They have a positive charge and are present in the nucleus of an atom along with the neutrons.
Answer:
A
Explanation:
The answer is A because proton number is the same as atomic number
Minh spent the weekend on his Wii and now has carpal tunnel syndrome. His 120 V outlet has an electrical current of 8A. What is the resistance in the Wii?
The resistance is 15 ohms.
Also, it's dissipating 960 watts whenever it's turned on. So it's almost as hot as a toaster, and Minh no longer has hands.
Calculate the Kinetic energy of: 1. a rabbit weighing 10
kg moving at a speed of 5 m/s.
Answer:
125
Explanation:
use the formula e=1/2mv² and use m=10 and v=5
this produces the equation e=1/2x10x25=125
dont forget the units (J) ;)
Answer:
125J
Explanation:
K.e=1/2mv^2
=1/2(10)(5)^2
=125J
A baseball sits motionless near first base on a baseball diamond. What statement best explains why the baseball remains motionless?
Answer:
Explanation:
Newton's first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force. This postulate is known as the law of inertia.
hope this helps :))
There is no force acting on the baseball the statement best explains why the baseball remains motionless.
What is inertia?A body wants to remain in its original position until or unless the external force is not applied to it. Such a phenomenon is known as inertia.
Newton's first law asserts that if a body is at rest or traveling at a uniform speed in a straight direction,
It will remain at rest or continue to move in a straight path at a constant speed until acted on by a force. This is referred to as the law of inertia.
There is no force acting on the baseball the statement best explains why the baseball remains motionless.
Hence option B is correct.
To learn more about the inertia refer to the link;
https://brainly.com/question/3268780
The National Aeronautics and Space Administration (NASA) studies the physiological effects of large accelerations on astronauts. Some of these studies use a machine known as a centrifuge. This machine consists of a long arm, to one end of which is attached a chamber in which the astronaut sits. The other end of the arm is connected to an axis about which the arm and chamber can be rotated. The astronaut moves on a circular path, much like a model airplane flying in a circle on a guideline. The chamber is located 20.0 m from the center of the circle. At what speed must the chamber move so that an astronaut is subjected to 5.64 times the acceleration due to gravity
Answer:
w = 1,662 rad / s, v = 33.25 m / s
Explanation:
This this exercise indicates that the acceleration felt by the astronauts is
a = 5.64 g
in a circular motion the centripetal acceleration is
a_c = v²/ r
angular and linear variables are related
v = w r
we substitute
a_c = w² r
we finally have
5.64 g = w² r
w² = 5.64 g / r
let's calculate
w = [tex]\sqrt{ \frac{5.64 \ 9.8}{20.0} }[/tex]
w = 1,662 rad / s
linear velocity is
v = w r
v = 1,662 20
v = 33.25 m / s
A car travels for 10s at a steady speed of 20 m/s along a straight road. The traffic lights ahead change to red, and the car slows down with a constant deceleration, so that it halts after a further 8s.
Answer:
The right solution is "2.5 m/s²". A further explanation is given below.
Explanation:
The given values are:
Initial velocity,
= 20 m/s
Final velocity,
= 0 m/s
Time,
= 8 s
As we know,
⇒ [tex]Acceleration=\frac{Final \ velocity-Initial \ velocity}{2}[/tex]
On substituting the values, we get
⇒ [tex]=\frac{0-20}{8}[/tex]
⇒ [tex]=\frac{-20}{8}[/tex]
⇒ [tex]=-2.5 \ m/s^2[/tex]
is silver magnetic or not ?
Answer:
Yes, but its magnetic power is very weak so its not that noticeable to the average person whos not paying attention.
What will be the final velocity of a rock if we drop it off of a bridge and it strikes the ground 2.8s later (ignoring air resistance)?
plzz help mee
What do you notice about how we write out the symbols for the different elements?
Many of the symbols are the first one or two letters of the element’s name in English. The first letter of a symbol is always written as a capital letter (uppercase) and the second letter as a small letter (lowercase).
For example
(i) hydrogen, H
(ii) aluminium, Al and not AL
(iii) cobalt, Co and not CO.
Symbols of some elements are formed from the first letter of the name and a letter, appearing later in the name.
Examples are: (i)chlorine, Cl, (ii) zinc, Zn etc.
Other symbols have been taken from the
names of elements in Latin, German or Greek.
For example, the symbol of iron is Fe from its Latin name ferrum, sodium is Na from natrium, potassium is K from kalium. Therefore, each element has a name and a unique chemical symbol.
PLEASE EXPLAIN IN TWO PARAGRAPHS (A PARAGRAPH IS 4-5 SENTENCES) SOME HEALTHFUL TIPS THAT CAN HELP PREVENT YOU FROM GETTING PHYSICAL FITNESS INJURIES.
Answer:
A workout injury can happen to anyone, no matter your experience or fitness level. People hurt themselves in all kinds of ways when they work out. Even walking can cause an injury. But you can significantly cut your risk of getting hurt by following certain workout precautions. There are simple steps that can help keep you injury-free during your workout.
Every workout should begin with a warm-up and end with a cool-down period. A warm-up helps your body get ready for exercise. It gradually increases your heart rate and loosens your muscles and joints. Cool-down after you work out so, it brings your heart rate back to normal. Walking for 5 to 10 minutes after you work out is one way to cool down. Do dynamic stretching before and after you work out. This will help increase flexibility. Don't push yourself too hard. As your fitness abilities increase and you will be able to challenge yourself more.
Hope this helps
Maintaining physical fitness is very important in today's world. Each and everyone should be involved in physical fitness.nowaday people are so busy with their work that they have forgotten health is wealth.
Even if we get engaged in physical fitness activity we can some time get insuries . some of tips that can help prevent from getting physical fitness injury, warm up exercises should be done before exercise to avoid muscle strength.safety precautions should be taken if you are dealing with heavy objects .
hence we should maintain physical fitness with getting rid of injury that may occur
mark me
The _____________ variable is observed, measured, and affected by the independent variable.
Answer: It would be the dependent variable.
Explanation:
The dependent variable is limited and can be affected by the changes and manipulation of the independent variable.
A truck with a mass of 15,000 kg moving at 25 m/s crashes into the back of a small 1,100 kg car moving at 15 m/s. They
stick together after the collision. Calculate the momentum of the system before the collision and after the collision.
Explanation:
Given that,
Mass of a truck = 15,000 kg
Speed of the truck = 25 m/s
Mass of car = 1,100 kg
Speed of the car = 15 m/s
As they stick together after the collision. Let V be the speed after the collision.
Initial momentum of the system,
[tex]P_i=15000\times25+1100\times15\\\\=391500\ kg-m/s[/tex]
Final momentum of the system,
[tex]P_f=(15000+1100)V\\\\=16100V[/tex]
Hence, this is the required solution.
A net force of 40 N south acts as an object with a mass of 20kg. What is the object's acceleration
Answer:
a = 2 m/s²
Explanation:
Given: 20 g, 40N
To find: Acceleration (a)
Solution: To find the acceleration (A), divide the force by the weight
A = F ÷ m
= 40 ÷ 20
= 2 m/s²
Newtons are derived units, equal to 1 kg-m/s². In other words, a single Newton is equal to the force needed to accelerate one kilogram one meter per second squared.
a transfer of energy without a transfer of mass describes what?
Explanation:
Wave motion
ex...longitudinal wave.