the distance between a boy and a hill is 250 meters. if the boy shouts after how long will the echo be heard numerical problem
Answer:
1.47 s
Explanation:
From the question,
s = 2d/t................... Equation 1
s = speed of sound in air, d = distance between the boy and the hill, t = time to hear the echo.
make t the subject of the equation
t = 2d/s............... Equation 2
Given: d = 250 meters
Constant: s = 340 m/s
Substitute these values into equation 2
t = (2×250)/340
t = 500/340
t = 1.47 s
What are tectonic plate boundaries?
A areas where Earth’s core experiences a high amount of stress
B areas where Earth’s core experiences a low amount of stress
C areas where Earth’s crust experiences a high amount of stress
D areas where Earth’s mantle experiences a high amount of stress
Answer:
c
Explanation:
Answer:
Areas where earth crust experiences a high amount of stress
Explanation:
FCAT review question
The latent heat of fusion for Aluminium is 3.97 x 105. How much energy would be required to melt 0.75 kg of it?
Answer:
[tex]E = 2.9775\times10^5 J[/tex]
Explanation:
Given: The latent heat of fusion for Aluminum is [tex]L = 3.97\times10^5 J/Kg[/tex]
mass to be malted m = 0.75 Kg
Energy require to melt E = mL
[tex]E = 3.97\times10^5\times0.75 = 2.9775\times10^5 J[/tex]
Therefore, energy required to melt 0.75 Kg aluminum
[tex]E = 2.9775\times10^5 J[/tex]
HELPPPP PLSSS I NEED HELP
Answer:
D. Pearl Harbor
Explanation:
30 kg sits on a table the acceleration due to gravity is 10 m/s^2 what force does the table exert on the television.
0.3N
3N
300N
600N
Answer:
300N
Explanation:
F=m×a
F=30kg×10m/s^2
F=300N
If 30 kilograms sit on a table the acceleration due to gravity is 10 meters/second², then the force exerted by the table on the television would be 300 Newtons,
Therefore the correct answer is option C.
What is acceleration?The rate of change of the velocity with respect to time is known as the acceleration of the object.
As given in the problem If 30 kilograms sit on a table the acceleration due to gravity is 10 meters/second²,
the force exerted = mass × acceleration due to gravity
= 30 kilograms × 10 meters/second²
= 300 Newtons
Thus, the force exerted by the table on the television would be 300 Newtons,
To learn more about acceleration from here, refer to the link;
brainly.com/question/2303856
#SPJ2
How would the motion of the book change if there was LESS friction as it moved across the table?
Answer:
The motion of the book would change if there was less friction if it moved across the table is that it would spin and have more kenetic energy.
Explanation:
friction slows stuff down so if it had less friction it would speed up and spin when sliding.
A piece of brass of mass 20.0g is hung on a sprong balance from a rigid support and completely immersed in kerosene of density 8.0 ×10 kgm-³. Determine the reading on the spring balance(g =10m/s², density of brass =8.0×10kgm-³)
1. interpret data- based on the data, describe what alicia did.
2. draw conclusions- what conclusions can you draw? what does stirring do in terms of heat transfer?
help :(
4. Un móvil viaja en línea recta con una velocidad media de 1200 cm/s durante 9 s, y luego con velocidad media de 480 cm/s durante 7 s, siendo ambas velocidades del mismo sentido: a) ¿cuál es el desplazamiento total en el viaje de 16 s? B) ¿cuál es la velocidad media del viaje completo?
Answer:
A) El desplazamiento total del viaje es 14160 centímetros.
B) La velocidad media del viaje completo es 885 centímetros por segundo.
Explanation:
A) El desplazamiento es el producto de la velocidad media por el tiempo. El desplazamiento total es la suma de desplazamientos asociados a cada velocidad media, entonces:
[tex]x = \left(1200\,\frac{cm}{s}\right)\cdot (9\,s)+ \left(480\,\frac{cm}{s} \right)\cdot (7\,s)[/tex]
[tex]x = 14160\,cm[/tex]
El desplazamiento total del viaje es 14160 centímetros.
B) La velocidad media del viaje es el desplazamiento total dividido por el tiempo total, es decir:
[tex]\bar v = \frac{14160\,cm }{16\,s}[/tex]
[tex]\bar v = 885\,\frac{cm}{s}[/tex]
La velocidad media del viaje completo es 885 centímetros por segundo.
How many degrees equal π in radians? How many revolutions (turns) equal π radians?
Answer:
It follows that the magnitude in radians of one complete revolution (360 degrees) is the length of the entire circumference divided by the radius, or 2πr / r, or 2π. Thus 2π radians is equal to 360 degrees, meaning that one radian is equal to 180/π ≈ 57.295779513082320876 degrees.
Explanation:
eating disorder Symptoms
Answer:
some symptoms can be lack of energy, and dizziness.
Explanation:
Una botella vacía tiene una masa de 24.25g y de 86.55g completamente llena de agua, se vacia el agua y se llena nuevamente con 123.95g de solvente tetracloruro de carbono, ¿cual es la densidad del solvente?
Answer:
La densidad del tetracloruro de carbono es 1.990 gramos por centímetro cúbico.
Explanation:
La masa de agua contenida dentro de la botella es igual a la diferencia entre la masa pesada totalmente llena y la masa pesada totalmente vacía, es decir:
[tex]m_{w} = 86.55\,g-24.25\,g[/tex]
[tex]m_{w} = 62.3\,g[/tex]
Ahora, de acuerdo con la definición de densidad, la masa es directamente proporcional a la densidad, entonces, podemos calcular la densidad del solvente mediante la siguiente relación:
[tex]\frac{m_{x}}{m_{w}} = \frac{\rho_{x}}{\rho_{w}}[/tex] (1)
Donde:
[tex]m_{x}[/tex] - Masa del tetracloruro de carbono, en gramos.
[tex]m_{w}[/tex] - Masa del agua, en gramos.
[tex]\rho_{x}[/tex] - Densidad del tetracloruro de carbono, en gramos por centímetro cúbico.
[tex]\rho_{w}[/tex] - Densidad del agua, en gramos por centímetro cúbico.
Si sabemos que [tex]m_{x} = 123.95\,g[/tex], [tex]m_{w} = 62.3\,g[/tex] y [tex]\rho_{w} = 1\,\frac{g}{cm^{3}}[/tex], entonces la densidad del tetracloruro de carbono es:
[tex]\rho_{x} = \left(\frac{m_{x}}{m_{w}} \right)\cdot \rho_{w}[/tex]
[tex]\rho_{x} = 1.990\,\frac{g}{cm^{3}}[/tex]
La densidad del tetracloruro de carbono es 1.990 gramos por centímetro cúbico.
What keeps planets in orbit? (i need help asap please T-T 10 points im low on points sorry)
A. Centrifugal force.
B. light energy
C. Gravity
D. All of the Above
Answer:
the answer is C gravity
Explanation:
When you are aware that you are having a dream and can control what you do
in that dream, it's called: ??
A. night terrors.
B. sleepwalking.
C. Stage 4 sleep.
D. lucid dreaming.
Answer:
D. lucid dreaming
Explanation:
(=^w^=)
what celestial body is cloest to earth
Answer:
Mercury
Essentially because Mercury is closest to the Sun, when taking an average over time, Mercury is the closest planet to the Earth, and - in that measure - it is the closest planet to each of the other planets in the Solar System.
Explanation:
What is the main function of b-cells?
B. They attack cells of the body that are infected.
None of these
A. They create antibodies.
They signal other lymphocytes to go after the pathogens.
Answer: They create antibodies.
Which feature causes a gap in the geologic record?
extrusion
fault
intrusion
erosion
Answer:
A
Explanation:
Answer : a. Extrusion
how does electricity work?
Answer:Electricity works by getting a bunch of conductor elements together and creating a flow of electron-stealing patterns through them. This flow is called a current. ... Once you can control the direction the electrons are going, you can use them to power or charge anything from a light bulb to your TV to your electric car.
Explanation:trust
A system releases 150 kJ of heat while 10 kJ of work is done on the system by
the surroundings. Calculate the change in internal energy (in kJ).
Answer:
160J OR 140J
Explanation:
Depends on teacher which formula your teacher uses.
U=Q+W OR U=Q-W
Method 1:
U=150+10J=160
U=150-10=140J
What are the prevailing winds from the west toward the east called?
Prevailing Westerlies
Jet Stream
Gulf Stream
La Nina
Answer:
The Coriolis Effect, in combination with an area of high pressure, causes the prevailing winds—the trade winds—to move from east to west on both sides of the equator across this 60-degree "belt."
Explanation:
if its wrong welp sorry that what i know,
Which of the following is the best example of a heat conductor?
Answer:
Anything with a dark shade in color and with no reflective surface or any metalExplanation:
In this case, a dark shirt or blanket would be a heat conductor as well as metal would be, too
GIVING BRAINLIEST PLEASE HELP!!
-if you answer correctly ill give you brainliest which will give you 25pts-
In a clear cup there are three substances. Their densities are 3, 1, and 2. From top of the cup to the bottom, what would the order of substances be sitting inside the cup?
Answer:
1, 2 and 3
Explanation:
The most dense substance will settle at the bottom of the cup
What force is caused by tiny collisions, called microwelds, on surfaces that
are stuck together?
A. heat
B. energy
C. air resistance
D. friction
Answer:
D. Friction
Explanation:
"Friction is caused by microwelds that form between two surfaces. Microwelds are stronger when the two surfaces are pushed together with a greater force." - ( Module 3 • Forces and Newton’s Laws) quoted
hope this helps and is right. p.s. i really need brainliest :)
Answer:
Friction
Explanation:
Took The Test
A vertical piston-cylinder device initially contains 0.1 m^3 of air at 400 K and 100 kPa. At this initial condition, the piston is resting on a stop. The piston-cylinder device is connected to a supply line with air at 400 K and a pressure of 500 kPa. The valve between the supply line and the piston-cylinder device is opened and is left open until the pressure in the piston-cylinder device reaches 500 kPa. The piston is observed to start moving when the pressure in the cylinder is 200 kPa and the piston continues to rise until it reaches a second stop. At the second stop, the piston-cylinder volume is 0.2 m^3 . The final temperature and pressure in the piston-cylinder device are 440 K and 500 kPa, respectively. Determine the heat transfer to or from the piston-cylinder device for the filling process Determine heat transfer (kJ) during the entire process.
Answer:
[tex]Q=-38.15kJ[/tex]
Explanation:
From the question we are told that
Piston-cylinder initial Volume of air [tex]v_1=0.1 m^3[/tex]
Piston-cylinder initial temperature [tex]T_1=400k[/tex]
Piston-cylinder initial pressure [tex]P_1= 100kpa[/tex]
Supply line temperature[tex]T_s=400k[/tex]
Supply line pressure [tex]P_s= 500kpa[/tex]
Valve final pressure [tex]P_v=500kpa[/tex]
Piston movement pressure [tex]P_m=200kpa[/tex]
Piston-cylinder final Volume of air[tex]v_2=0.2 m^3[/tex]
Piston-cylinder final temperature [tex]T_2=440k[/tex]
Piston-cylinder final pressure [tex]P_2= 500kpa[/tex]
Generally the equation for conservation of mass is mathematically given by
[tex]Q=m_2 \mu_2-m_1 \mu_1 +W-(m_2-m_1)h[/tex]
where
Initial moment
[tex]m_1=\frac{p_1 V_1}{RT_1}[/tex]
[tex]m_1=\frac{100*0.1}{0.287*400}[/tex]
[tex]m_1=8.7*10^-^2kg[/tex]
Final moment
[tex]m_2=\frac{p_2 V_2}{RT_2}[/tex]
[tex]m_1=\frac{500*0.3}{0.287*440}[/tex]
[tex]m_1=79*10^{-2}kg[/tex]
Work done by Piston movement pressure
[tex]W=Pd[/tex]
[tex]W=P(v_2-v_1)[/tex]
[tex]W=200(0.2-0.1))[/tex]
[tex]W=20000J[/tex]
Heat function
[tex]h=cT_1[/tex]
[tex]h=1.005(400)[/tex]
[tex]h=402[/tex]
Therefore
[tex]Q=(0.792*0.718(440)-0.0871*0.718(400)+20-(0.792-0.087)*402))[/tex]
[tex]Q=-38.15kJ[/tex]
It is given mathematically that the system lost or dissipated Heat of
[tex]Q=-38.15kJ[/tex]
A car is traveling constant spoed ol 12 12 m/s When the driver accelerates, the car reaches a speed of 26 m/s in s What is the average acceleration of the
Answer:
Average acceleration of the car is 1.167 m/s^2
Explanation:
The speed of car with which it is travelling is 12 m/s
As the driver accelerates the car, the speed reaches 26 m/s
The change in speed in 12 seconds is
26 -12 = 14 m/s
Average acceleration is change in speed divided by time
[tex]\frac{14}{12} \\1.167[/tex] m/s^2
Which of these provides the best explanation for why the pencil appears broken?
A. The pencil absorbs all the light rays that hit it
B. Water reflects light rays away from the pencil
C. Light rays are bent by the water in the glass
D. The surface of the water reflects lights rays
C. Light rays are bent by the water in the glass.
Explanation:
The light defracts as is it leaves the medium of air and enters the medium of the water/glass.
The link below is to a short video that explains this concept very well.
https://youtu.be/Iq1a_KJTWJ8
I can someone help me and also I gtg so ill be back in a bit
Answer: No sure what to do
Explanation: points for points
The horizontal distance between two nodes is 1.5 meters what is the wavelength of then standing wave
Answer:
[tex]\lambda=3\ m[/tex]
Explanation:
Given that,
The horizontal distance between the two nodes is 1.5 meters.
We need to find the wavelength of the standing wave.
If we know the distance between nodes and antinodes, then the equation is :
[tex]\dfrac{\lambda}{2}=D[/tex]
Where
[tex]\lambda[/tex] is the wavelength
So,
[tex]\lambda=2D\\\\=2\times 1.5\\\\=3\ m[/tex]
So, the wavelength of the standing wave is equal to 3 m.
which vector is the sum of vectors a and b
Answer:
C
Explanation:
Vector A points up
Vector B points right
The combination must be both up and right which is C