The frequency observed by Francis when the train approaches is 297.4 Hz.
Doppler effect
The frequency observed by Francis is determined by applying the principle of Doppler effect.
The frequency observed by Francis is calculated as follows;
[tex]f = f_o(\frac{V}{V \pm V_s} )[/tex]
where;
f is the source frequencyf₀ is the observed frequencyVs velocity of the source when it is moving towards the observerV is velocity of sound45 km/h = 12.5 m/s
Speed of sound in air = 343 m/s
Since the train is moving towards the observer, the frequency heard by the observer will be greater than the source frequency, thus we will choose positive sign for the source velocity.
[tex]f = f_o(\frac{V}{V + V_s} )\\\\287 = f_0 (\frac{343}{343+ 12.5)} )\\\\287 = 0.965f_0\\\\f_0 = \frac{287}{0.965} \\\\f_0 = 297.4 \ Hz[/tex]
Thus, the frequency observed by Francis when the train approaches is 297.4 Hz.
Learn more about Doppler effect here: https://brainly.com/question/3841958
1. A 250g bullet is fired with a speed of 300m/s. if it stopped after hitting a target 150m away, (a) what is its initial kinetic energy? (b) What is the magnitude of the force that stopped it? 2. Determine the GPE of a 0.5kg object when it is raised (a.) 0.75m from the floor. (b) What happens to its GPE if we double the height? 3. How high could a 40kg mass be lifted if an energy of 2x10^6 J is used in lifting it?
Answer:
See below
Explanation:
KE = 1/2 m v ^2
= 1/2 (250/1000) 300^2 j the bullet is 250/1000 kg ( assuming g is grams and not GRAINS - in which bullet weight is usually measured)
force to stop it is the same number
PE = mgh = .5 *9.81 * .75 =
doubling height will double PE
2 x 10^6 = 40 * 9.81 * h sove for 'h' in meters
Initial kinetic energy is 11250 J and magnitude of force to stop bullet is 75 N.
The GPE for 0.75m height floor is 3.75J.
The GPE for double of 0.75m height is 7.5J.
The high on which 40 kg mass is lifted is 5000m.
What is kinetic energy?The kinetic energy of an object is the energy that it possesses due to its motion.
[tex]KE = 1/2 m v ^2[/tex]
[tex]=1/2 (250/1000) 300^2 J\\= 11250 J[/tex]
Work done,
[tex]W= fs\\\\f=\frac{W}{s}\\\\f=\frac{11250}{150}[/tex]
[tex]f=75 N[/tex]
What is GPE?Gravitational potential energy is the potential energy a massive object has in relation to another massive object due to gravity.
PE = mgh
= .5 *9.81 * .75
= 3.75 J
Potential energy when height doubles = 7.5J
What is height to which object lift?The potential energy is given by
[tex]PE = mgh\\\\h = PE/ mg\\\\h = 2*10^6 J /40*9.8\\\\h = 5000 m[/tex]
To learn more about Kinetic and potential energy here
https://brainly.com/question/15764612
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The blood travels through the body in tubes called
Blood travels through the body in tubes called arteries and veins.
What are blood vessels?Blood vessels are tubes through which the blood circulates in the body. Blood vessels include the following;
network of arteries, arterioles, capillaries, venules and veinsThus, we can conclude that blood travels through the body in tubes called arteries and veins.
Learn more about blood vessels here: https://brainly.com/question/25149738
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Heat Capacity is a measure of the heat required to raise the temperature
of 1g of a substance by 1°C.
So...
True or False:
Water has a very high heat capacity, which means it resists changing
temperature when heat is added or removed.
A
True
B
False
Answer: i would say true uwu
Explanation:hope this helps!
....Max-
what is the force needed to accelerate a grocery sack weighing 212 N upward at 1.7 m/s2
Answer:
36.04N
Explanation:
accelerating force: mass × acceleration
F=ma
m=212/10= 21.2kg
a=1.7m/s2
F=21.2×1.7
=36.04N
Can there be situation when velocity is constant but speed is not
Answer:
yes
Explanation:
as speed is a scalar quantity and velocity is a vector quantity. Which means speed only depends on the magnitude at which it travels but velocity depends on the speed at which travel and also the direction to where the object travels.
pls mark as brainliest
CAN ANYONE HELP ME???????????
Answer:
D -- 12
Explanation:
Hope this helps! Please let me know if you need more help or think my answer is incorrect. Brainliest would be MUCH appreciated. Also remember to rate answers to help other students, While leaving thanks to answers that help you. Have a great day!
If the same object was taken to each of the planets, where would it weigh the most and where would it weigh the least
Answer:
it way the most on jupiter and the least on mars
Explanation:
It's a frightening idea, but what would be the sound intensity level of 100 physics professors talking simultaneously
The sound intensity level of 100 physics professors talking simultaneously is equal to 72 decibel.
Given the following data:
Sound intensity = 52 dB.What is sound intensity?Sound intensity can be defined as a measure of the power of a sound wave per unit area. Thus, sound intensity is a quantity that can be used to measure the energy of sound and its unit of measurement is Watts per square meter.
How to calculate the sound intensity level.Mathematically, sound intensity level is given by this formula:
[tex]\beta = 10 log(\frac{I}{I_{ref}} )[/tex]
Note: The reference value of sound intensity is equal to [tex]1.0 \times 10^{-12}\;W/m^2[/tex]
Thus, the sound intensity for one (1) professor is given by:
[tex]I_1 = 1.0 \times 10^{-12} \times 10^{5.2}\\\\I_1=1.585 \times 10^{-7}\;W/m^2[/tex]
For 100 professors, the sound intensity is:
[tex]I_{100} = 1.585 \times 10^{-7} \times 100\\\\I_{100}=1.585 \times 10^{-5}\;W/m^2[/tex]
Substituting the parameters into the formula, we have;
[tex]\beta = 10 log(\frac{1.585 \times 10^{-5}}{1.0 \times 10^{-12}})\\\\\beta = 10 log(15.58 \times 10^{6})\\\\\beta = 10 \times 7.2\\\\\beta =72\;dB[/tex]
Read more on sound intensity here: https://brainly.com/question/17062836
Complete Question:
One physics professor talking produces a sound intensity level of 52 dB. It's a frightening idea, but what would be the sound intensity level of 100 physics professors talking simultaneously?
Answer:
72dB
Explanation:
The sound intensity level of one prof is given, that's your β1 (which is equal to 52dB).
Using the sound intensity level formula:
β1= 10log ([tex]\frac{I}{I_{o} }[/tex]) = 52 dB
*This will be useful later on [even if β1 is known]
Set up the formula for β2 (β2 is going to be the new sound intensity, the one for the 100 profs):
β2 = 10 log( [tex]\frac{ 100 I}{I_{o} }[/tex] )
*You need to multiply the intensity of one professor by 100 (because now there's more)
*do some algebra- pull out the 100
β2 = 10 log (100 [tex]\frac{I}{I_{o} }[/tex])
*use log laws
β2 = 10 ( log(100) + log ([tex]\frac{I}{I_{o} }[/tex]) )
*Now, isn't there a familiar part? Well, yes! The expression for β1!
β2 = 10log(100) + β1
β2 = 10log(100) + 52dB
*use your calculator
β2 = 73dB
^^^ that's your new sound intensity level
friction causes kinetic energy to be converted into
A. Potential energy
B. Thermal energy
C.mechanical energy
D. Electrical energy
Which one is it pls help me
Answer:
Thermal Energy
Explanation:
When friction acts between two surfaces that are moving over each other, some kinetic energy is transformed into heat energy. Otherwise known as thermal energy.
What is it called when something with kinetic energy(something moving) hits something that is still / has potential energy
Answer:
It is called Motion Energy
Explanation:
Cacharrerosdelaweb. Com 2019 12 que es keylogger html.
Los keyloggers son software o hardware que tienen la función de guardar la información que se escribe en el teclado de una computadora.
¿Qué es keylogger?Un keylogger es un término para referirse a un software o hardware que tiene la función de seguir y registrar todas y cada una de las pulsaciones que se hacen en el teclado de una computadora.
Generalmente, los keyloggers son formar ilícitas de obtener información confidencial del usuario de un computador sin su consentimiento. En los últimos años, se ha relacionado a los keyloggers con actividad digital delictiva debido a que es una de las formas que utilizan los criminales para robar información confidencial como cuentas bancarias.
Aprenda más sobre keyloggers en: https://brainly.com/question/17231901
Which types of interactions are negligible at standard temperature and pressure?
Explanation: a reduction in genetic diversity and discomfort for animals that have very exaggerated characteristics.
what the equation for speed?
Answer:
Speed Formula:
[tex]s = \frac{d}{t} [/tex]
The main factors in determining your speed on an acceleration lane are:.
Answer:
amount and speed of traffic on the acceleration lane and expressway.
chemical process where a solid turns into a gas without going through a liquid stage.
(A) witchcraft
(B) sublimation
(C) potential phase
Answer:
B) sublimation
Explanation:
An example is the vaporization of frozen carbon dioxide (dry ice) at ordinary atmospheric pressure and temperature.
Answer:
sublimation
Explanation:
sublimation, in physics, conversion of a substance from the solid to the gaseous state without its becoming liquid. An example is the vaporization of frozen carbon dioxide or dry ice(CO2)
or Solid Chlorine (Cl2) at ordinary atmospheric pressure and temperature. The phenomenon is the result of vapour pressure and
temperature relationships.
Please Mark me Brainiest
The gravitational pull of the sun is greatest in our solar system because it...
A. is the brightest
B. has the greatest mass
C. has the greatest magnetism
Answer:
B. has the greatest mass
Explanation:
mass & distance affect pull
grativy affects speed & shape of orbit of the planet
quiziz
5. How much time does it take for a bird flying at a speed of 45 kilometers per hour to travel a
distance of 1800 kilometers
Answer:
[tex]40h[/tex]
Explanation:
Use the velocity formula to solve
[tex]v = \frac{d}{t}[/tex]
In this question, you are given velocity [tex]v = 45km/h[/tex], and you are given a distance, [tex]d = 1800km[/tex]. Time in this question is what you'll need to find.
Start by rearranging the velocity formula, to isolate for t.
[tex]v = \frac{d}{t}[/tex]
Start by multiplying both sides by t
[tex]v(t) = \frac{d}{t}(t)\\\\vt = d[/tex]
Then divide both sides by v.
[tex]vt\frac{1}{v} = d/v\\ \\t = \frac{d}{v}[/tex]
Now that you've isolated for time, sub in your values and calculate.
[tex]t = \frac{d}{v} = \frac{1800km}{45km/h} = 40 h[/tex]
BRAINLIEST!!! how did the intensity of a sound wave change if the distance from the source is decreased by a factor of 2? Right answers only!!!
a. the intensity increases by a factor of 4
b. the intensity increases by a factor of 2
c. the intensity decreases by a factor of 2
d. intensity decreases by a factor of 4
Answer:
D.
Explanation:
The answer should be D. because if it increases by a factor of 2 then it will decrease at a factor of 4.
I hope it helps! Have a great day!
Anygays-
an object from 10.0 meters. She knows it had 50.0 joules of potential energy. How much mass does it have?
Answer:
5N
Explanation:
Work done by a constant force is given by the following equation:
W=F⋅d⋅cos(θ)
where F is the applied force, d is the distance over which the force is applied, and θ is the angle between the force and displacement vectors.
In this case, the work is done by gravity, and as the object is assumed to fall straight down, θ=0^o.
We know that the force of gravity acting on an object can be expressed by FG=mg, and for an object which is not accelerating (e.g. a stationary object), this is equal to the object's weight.
We know d=10m,θ=0^o and W=50J, so we can solve for F to find the object's weight. ⇒F=Wdcos (θ) But cos (0^o)=1, so: F=Wd=50J10m=5N
what is work done constant force
Answer:
W=Fd
This is the equation for it
The symbol equation for combustion of a hydrocarbon is shown below. What number will go before the oxygen reactant when this equation is balanced?
Answer:
5 Oxygen , 3 Carbon dioxide and 3 water
Answer: the answer is 5
I REALLY NEED HELP!!!!
4. The pressure under the tyres of a tractor is 60 000 Pa. The pressed area is 0.5 m². How much
is the weight of the tractor?
Answer:
weight = 30000 Newton
Given:
pressure: 60,000 Paarea: 0.5 m²========================
[tex]\sf pressure \ (Pa)=\dfrac{force \ (N)}{area \ (m^2)}[/tex]
[tex]\dashrightarrow \sf \ 60 000 = \dfrac{force}{0.5}[/tex]
[tex]\dashrightarrow \sf \ force =60 000 *0.5[/tex]
[tex]\dashrightarrow \sf \ force =30000 \ N[/tex]
========================
Weight is the force due to gravity.
Thus, force = gravity = 30000 N
How much work is done by a constant horizontal 20-N force pushing a 50-kg block a distance of 10 m on a horizontal surface
Answer:
200 Nm
Explanation:
Work Done by Particular Force = Particular Force × Distance
A police car is asked to overtake a red sedan that is 16 km ahead of it on the freeway. The red sedan is traveling at 80 km/hr and the police car travels at 100 km/hr. When will the police car overtake the sedan?
Answer:
S = v0 t + 1/2 a t^2 a = 0 seems given in the problem
Vp t = Vr t + 16
both travel for time t but the police car is going faster and travels 16 km farther
t (Vp - Vr) = 16
t = 16 km / (100 - 80) km/hr
t = 16 / 20 hr = 4/5 hr = 48 min
Questions #19 and 20:
Part 1 of 2: A Carnot engine has a power output of 122 kW. The engine operates between two reservoirs at 9 °C and 458 °C. How much thermal energy is absorbed each hour? Answer in units of J.
Part 2 of 2: How much thermal energy is lost per hour? Answer in units of J.
(1) The thermal energy absorbed by the Carnot engine is 7.15 x 10⁸ J.
(2) The thermal energy lost per hour by the Carnot engine is 2.75 x 10⁸ J.
Thermal energy entering the heat engineThe thermal energy absorbed by the heat engine is calculated as follows;
[tex]Q_h = \frac{P\Delta t}{1 - T_c/T_h}[/tex]
where;
Tc is the temperature of the cold reservoir = 9 + 273 = 282 KTh is the temperature of the hot reservoir = 458 + 273 = 731 K[tex]Q_h = \frac{(122,000) \times (3600)}{1 - \frac{282}{731} } \\\\Q_h = 7.15\times 10^8 \ J[/tex]
Thermal energy lost by the heat engineThe thermal energy lost per hour by the heat engine is calculated as follows;
[tex]Q_c = Q_h - P\Delta t\\\\Q_c = (7.15 \times 10^8 )\ - \ (122,000 \times 3600)\\\\Q_c = 2.75 \times 10^8 \ J[/tex]
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A car of mass 10.0 ks traveling at 5.00 m/s comes to rest due to friction after traveling 20.0 m. What is the work done on the car by the friction?
A. –125 J
B. –50 J
C. 50 J
D. 125 J
The work done on the car due to friction is -125 J.
What is workdone?Work is said to be done when a force moves an object through a certain distance.
To calculate the workdone on the car by friction, we use the formula below
Formula:
W = m(v²-u²)/2.......... Equation 1
Where:
W = Work done due to fricionm = mass of the carv = Final velocityu = Initial velocityFrom the question,
Given:
m = 10 kgv = 0 m/su = 5 m/sSubstitute these values into equation 1
W = 10(0²-5²)/2W = 5(-25)W = -125 JHence, The work done on the car due to friction is -125 J.
Learn more about work done here: https://brainly.com/question/21854305
Hello people ~
please help me with thie question attached above.
Thanks in advance!
Answer:
W = 1/2 x P x E
Explanation:
Let :
P = electric dipole momentE = uniform electric fieldα = initial angleβ = final angleFormula
The work done in a electric field can be found using the formula :W = P x E x (cosα - cosβ)Solving
W = P x E x (cos0° - cos60°)W = P x E x (1 - 1/2)W = 1/2 x P x ELet's see
[tex]\\ \rm\rightarrowtail W=P\vec{E}(cos\theta_i-cos\theta_f)[/tex][tex]\\ \rm\rightarrowtail W=P\vec{E}(cos0-cos60)[/tex]
[tex]\\ \rm\rightarrowtail W=P\vec{E}(1-1/2)[/tex]
[tex]\\ \rm\rightarrowtail W=\dfrac{P\vec{E}}{2}[/tex]
Which of the following is the measure of average kinetic energy of the particles in a
substance?
А
Diffusion
B
Atmospheric Pressure
С
Temperature
D
Vapor Pressure
Answer:
The correct answer is C
Explanation:
Hope this helped :)
if im wrong pls tell me.
100 pts.
An object 8.25 cm from a lens creates a virtual image at -26.8 cm from the lens. What is the focal length of the lens?
(Mind your minus signs.) (Unit = cm)
Answer:
1 / f = 1 / i + 1 / o 1 / f = (o + i) / i o
f = i o / (o + i)
f = -26.5 * 8.25 / (8.25 - 26.8)
f = -221 / -.308 = 11.8 cm
define one kilogram mass
Answer:
The amount of a certain global prototype was created of platinum-iridium and held at the International Bureau of Weights and Measures.Explanation:
Hopes this helps.