An observer is standing next to the tracks, watching a train approach. The train travels at 30 m/s and blows its whistle at 8,000 Hz as it approaches and then passes by the observer without slowing down. Assuming the speed of sound is 340 m/s, how much of a frequency change did the observer hear?
Answer:
The frequency heard by the observer will be "7351.35 Hz".
Explanation:
The given values are:
Source,
[tex]V_s=30 \ m/s[/tex]
Frequency of source,
[tex]F_s=8000 \ Hz[/tex]
Speed of sound,
[tex]C=340 \ m/s[/tex]
As we know,
⇒ [tex]F=(\frac{C+V_r}{C+V_s} )F_s[/tex]
Here,
[tex]V_r=0[/tex]
So that the formula will be:
⇒ [tex]F=(\frac{C}{C+V_s} )F_s[/tex]
[tex]=\frac{340}{340+30}\times 8000[/tex]
[tex]=7351.35 \ Hz[/tex]
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Think about multiplying the mass of each student by a factor to calculate each student’s kinetic energy. Is there a common factor that works for every student? If so, what’s this factor?
Answer:
KE= (1/2)mv^2
given m, the remaining components of the equation are=
1/2v^2?
Explanation:
KE= (1/2)mv^2
plug in...
=(1/2)(27 kg)(3 m/s)^2= 121.5
KE= 121.5 J
Answer:
Multiplying the mass of any student by a factor of 4.5 gives the kinetic energy of the student.
Which device manages the flow of current in an electric circuit?
the wire
the switch
the battery
the light bulb
Answer:
b
Explanation:
Switch is the device that manages the flow of current in an electric circuit.
What is meant by current ?Current in a conductor is defined as the rate of flow of charge through the conductor per unit time.
Here,
An electric circuit consists of various components such as wire, switch, light bulb, battery, etc.
The wire is a piece of metal strand through which the current flows in an electrical circuit.
Switch is the device that controls the flow of current in an electric circuit by turning on and off mechanism.
Battery is the device that provides the necessary potential difference for the production of electrical energy in an electric circuit.
A light bulb is the device which is used to produce light from the electricity in an electric circuit.
Hence,
Switch is the device that manages the flow of current in an electric circuit.
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An object is dropped from a 32 m tall building. How fast will it be going when it
strikes the ground?
Answer:
If there is no air resistance, it would be
25.04 m/sec when it hits the ground
Please help!! i will mark brainly
Answer:
The object sped up, moved at constant speed, then slowed down.
Enzymes have a certain temperature at which they work best. Temperatures above and
below this point will decrease enzyme activity. Which graph best illustrates the effect of
temperature on enzyme activity?
Answer:
B
Explanation:
It shows the increase in temperature and the decrease.
The best activity of enzyme is It increases and decreases.
What are Enzymes?A biological catalyst called an enzyme is usually always a protein. It accelerates a certain chemical reaction in the cell.
The enzyme is continuously employed during the reaction and is not destroyed. Each enzyme molecule found in a cell is unique and tailored to a particular chemical reaction.
A biological catalyst called an enzyme is often a protein, though it can also be RNA. A catalyst's purpose is to quicken the rate at which a reaction takes place.
Therefore, The best activity of enzyme is It increases and decreases.
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help me to answer this please
Answer:
ok
Explanation:
A man walks 30 ft. East, then 25 ft. South. How far is the man away from where
he started?
39.05 ft
32 ft
16.6ft
10ft
HURRRY PLEASEEEEE!!!
In photosynthesis, what two compounds are produced during the light-dependent reaction then used in the light-independent reaction?
A) ATP and NADPH
B) ATP and ADP
C) NADP+ and ADP
D) NADPH and NADP+
Answer:
The answer choice is: A) ATP and NADPH
Explanation:
Your question is asking the components that are created during light - dependent reaction, and then used in independent reaction. That would be shown in the photo below!
ATP and NADPH is created from light dependent then transfered and transformed into different components from the calvin cycle (light independent cycle)
Two compounds are produced during the light-dependent reaction then used in the light-independent reaction - A) ATP and NADPH
Photosynthesis is a process that takes place in the Chloroplast of plant cells. Autotrophs obtain their energy source (food) in the presence of sunlight.
The photosynthesis process occurs in two distinct stages; light-dependent reaction and light-independent reactions.
the light reactions take place in the thylakoid membranes of chloroplasts.The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesisThese molecules are the energy storage molecule ATP and the reduced electron carrier NADPH.Thus, two compounds are produced during the light-dependent reaction then used in the light-independent reaction - A) ATP and NADPH
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a sled with no initial velocity accelerates at a rate of 3.2 m/s squared down a hill how long does it take to sled to go 15 m to the bottom
Answer:
After 3.06secondsExplanation:
Given that the following data are
acceleration a= 3,2m/s^2
distance s=15m,
time t=?
Applying the formula for the equation of motion we have
s=ut+1/2at^2
we no initial velocity (u=0)
substituting our given values into the expression we have
15=0*t+1/2(3.2)t^2
15=1/2(3.2)t^2
15=3.2t^2/2
30=3.2t^2
t^2=30/3.2
t^2=9.375
Squaring both sides we have
t=√9.375
t=3.06seconds
It will take the sled 3.06 seconds to get to the bottom
A mass is dropped from a height h above the ground, and freely falls under the influence of gravity. Which graphs here correctly describes the displacement and velocity of the object during the time the object is falling? Consider the "up" direction to be positive.
Which graph is it?
Answer:
B
Explanation:
The only force acting on the block is gravity, so the block has a constant, negative acceleration. This means the velocity of the block is decreasing at a constant rate, so the answer is B, D, or E. Velocity is the rate of change of displacement, and answer choice B is the only one that has a displacement graph that matches that idea.
Answer: Graph B here correctly describes the displacement and velocity of the object during the time the object is falling. Option B is correct.
It is given that the mass of an object is dropped from height 'h' above the ground and "up" direction is taken to be positive.
It is required to find the graph which describes the displacement and velocity of the object during the time the object is falling.
Which graphs here correctly describes the displacement and velocity of the object during the time the object is falling?If any body falls freely towards the ground, then its acceleration is decreasing constantly with respect to time. That means velocity of an object will also be decreased as shown in graph B. Also we know that velocity is the rate of change of displacement.
As it is given in question that up direction is positive then it is also considered that downward be negative means decreasing.
Therefore, both the quantities are decreasing. So graph B correctly describes the displacement and velocity of the object during the time the object is falling.
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What can a machine do?
O A. Decrease the work needed to do something
B. Make the work you do feel easier
C. Multiply the energy of a system
O D. Create energy in the form of work
Answer:
B. Make the work you do feel easier
Answer:
Something a machine can do is Decrease the work needed to do something and a machine can also do make the work you do easier.
Explanation:
Can an object experiencing constant acceleration change its direction of motion? Explain.
Answer:
Yes it can.
Explanation:
A object undergoing a constant acceleration has a constantly changing velocity. If the acceleration always points in the same direction as the velocity, the trajectory will be no different than if there were no acceleration, but in general acceleration will change the trajectory.
True or False: A reference point is stationary
Answer:
True
Explanation:
A Reference point is stationary
______ is a great example of a sport that creates a concentric contraction in
your muscles because the effort of lifting is short and powerful.
Dancing
Weightlifting
Horseback riding
Swimming
Answer:
weightlifting
Explanation:
Convert 2.5 mm to micrometers
Answer:
2500
Explanation:
Answer:
2500
Explanation: 1 mm is 1000 micrometers pls give me brainlist
Which one is correct for question 5?
Answer:
the object has a constant net force greater than zero acting on it.
Explanation:
A man runs at 7.5 m s-1 due east across the deck of a ship which moves at 10.0 m s-1 due north. Determine the resultant velocity of the man( his velocity relative to the water)
Answer:
12.5 m/s North/east
Explanation:
I thought of it as a graph. I basically just found the distance between the points (0,0) and (10, 7.5)!
The resultant velocity of the man is 12.5 m/s.
What is velocity?The rate at which a body's displacement changes in relation to time is known as its velocity. Velocity is a vector quantity with both magnitude and direction. SI unit of velocity is meter/second.
Velocity of the man: v₁ = 7.5 m/s (due east )
Velocity of the ship: v₂ = 10 m/s. ( due north.)
Hence, the man and the ship move in perpendicular direction.
So, his velocity relative to the water = the resultant velocity of the man
= √(7.5² + 10²) m/s = 12.5 m/s.
Hence, resultant velocity of the man is 12.5 m/s.
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The energy of electromagnetic waves increases with decreasing wavelength.
Which of the following statements support this claim?
O A. Dental patients need to wear lead aprons to protect themselves from X-rays but do not wear
protection from flashlights.
B. Both radio waves and gamma rays are invisible to human eyes.
C. Ultraviolet radiation causes sunburn but radio waves do not.
D. Microwaves are used for communication.
E. Gamma rays are used to kill cancer cells, but microwaves have no known effect on cancer
cells.
Answer: A C E
Explanation: i just did it and got it right lol
Answer:
its A, C, and E
Explanation:
i did it and got it right
If an automobile travels at 30 m/sec for 2 minutes, the car have traveled ?
Answer:
1800 times 2= 3600
Explanation:
what is universe made off
Answer:
I mean, correct me if I'm wrong for some reason, but I think its Matter?
Answer:
The Universe is thought to consist of three types of substance: normal matter, 'dark matter' and 'dark energy'. Normal matter consists of the atoms that make up stars, planets, human beings and every other visible object in the Universe.
Explanation:
What would happen if the electromagnet in an electric bell is replaced by an ordinary magnet
Answer:
The bell will not work as the Hammer will be attracted to the Gong and it will remain attracted because if there was an electromagnet the hammer will be released as soon as we stop pressing the switch but a Bar magnet is a permanent magnet and once it will get attracted to the Gong it will remain attracted.
Explanation:
Hope that helps!
If you run the 100 m track at a velocity of 5.0 m/s, what is the time needed?
How can you find the frequency or period of ocean waves?
Answer: As you probably have seen in the ocean or a lake, the stronger the wind, the higher the waves. The period and wavelength can be expressed in terms of their reciprocals, the wave frequency ω = 2(pi)/T, and the wave number κ = 2(pi)/λ.
Explanation: To find the period, we solve for T=1f, given the value of the frequency (f=2s−1). T=12 s−1=0. 5 s. Since one definition of wavelength is the distance a wave has traveled after one complete cycle (or one period), the values for the wavelength (λ=0.9m) as well as the frequency are given.
21. Compare and contrast beta particles to the electrons that surround neutral atoms.
UGH HELP MEEE PLSS
A runner is jogging in a straight line at a
steady vr= 8.4 km/hr. When the runner is
L= 6.3 km from the finish line, a bird begins
flying straight from the runner to the finish
line at vb= 42 km/hr (5 times as fast as the
runner). When the bird reaches the finish
line, it turns around and flies directly back to
the runner.
Answer:
Total distance traveled by bird is 10.5 km.
Explanation:
Given that,
Velocity of runner= 8.4 km/hr
Distance = 6.3 km
Velocity of bird = 42 km/hr
Suppose, How far does the bird travel?
We need to calculate the time of bird
Using formula of time
[tex]t=\dfrac{d}{v_{b}}[/tex]
Put the value into the formula
[tex]t=\dfrac{6.3}{42}[/tex]
[tex]t=0.15\ hr[/tex]
We need to calculate the distance runner travels during time period
Using formula of distance
[tex]d=v_{r}\times t[/tex]
[tex]d=8.4\times0.15[/tex]
[tex]d=1.26\ km[/tex]
We need to calculate the distance of runner to FL
Using distance
[tex]d'=6.3-1.26[/tex]
[tex]d'=5.04\ km[/tex]
We need to calculate the net closing speed between runner and bird
Using speed
[tex]v'=v_{r}+v_{b}[/tex]
[tex]v'=8.4+42[/tex]
[tex]v'=50.4\ km/hr[/tex]
We need to calculate the time for runner and bird to meet
Using formula of time
[tex]t=\dfrac{d}{v'}[/tex]
Put the value into the formula
[tex]t=\dfrac{5.04}{50.4}[/tex]
[tex]t=0.1\ hr[/tex]
We need to calculate the distance covered by runner
Using formula of distance
[tex]d=vt[/tex]
Put the value into the formula
[tex]d=8.4\times0.1[/tex]
[tex]d=0.84\ km[/tex]
We need to calculate the distance covered by bird to runner
Using formula of distance
[tex]d=vt[/tex]
Put the value into the formula
[tex]d=42\times0.1[/tex]
[tex]d=4.2\ km[/tex]
We need to calculate the total distance
Using distance
[tex]D=6.3+4.2[/tex]
[tex]D=10.5\ km[/tex]
Hence, Total distance traveled by bird is 10.5 km.
it takes you 30 minutes to walk an average velocity of 2.om/s south to school. What is your displacement?
Answer:
3600 m SOUTH
Explanation:
avg velocity= (change displacement)/(change in time)
2.0 m/s= x/ (1800 s)
displacement= (2.0 m/s * 1800s)= 3600 m SOUTH
.......
sign explanation
2.0 m/s south= -2.0 m/s (downwards direction)
-2.0 m/s= x/ (1800 s)
x= -3600 m
An object is said to move from a position of 10m East to a position of 5m west. Determine the object's distance travelled.
Answer:
5 i think
Explanation:
An athlete kicks a soccer ball with a velocity of 24.2 m/s at a 26 degree angle from the ground.
Find the horizontal component of the starting velocity. (Vx)
Answer: I got was 23.71 or if you round it it'd be 23.72 but it still says that I'm wrong
Answer:
The horizontal component is 18 cos(35) = 14.745 m/s
The vertical component is 18 sin(35) = 10.324 m/s
Explanation: