Answer:
The Doppler Effect is given by the following relation;
[tex]f' = \left (\dfrac{v + v_0}{v - v_s} \right) \times f[/tex]
Where;
f' = The frequency the observer hears
f = Actual frequency of the wave
v = The velocity of the sound wave
[tex]v_o[/tex] = The velocity of the observer
[tex]v_s[/tex] = The velocity of the source
Where the observer is stationary, we have;
(i) When the source is moving in the direction of the observer
[tex]f' = \left (\dfrac{v }{v - v_s} \right) \times f[/tex]
(ii) When the source is receding from the observer, we have;
[tex]f' = \left (\dfrac{v }{v + v_s} \right) \times f[/tex]
Therefore;
(a) A person left behind on the platform
For a person left behind on the platform, we have that the radio source is receding, therefore, we have;
[tex]f' = \left (\dfrac{v }{v + v_s} \right) \times f[/tex]
(1) Given that (v + [tex]v_s[/tex]) > v, therefore, v < (v + [tex]v_s[/tex]), f' < f, the frequency heard by the person left on the platform, f', is smaller (lower) than the frequency produced by the radio
(2) The frequency is not constant as the speed of the source is increasing while it under the acceleration due to gravity
(3) During the fall, the speed of the source continuously increases under the effect of gravitational attraction and therefore the frequency heard by the person on the platform becomes progressively smaller
(b) A person down below floating on a rubber raft
For the the person down below on the rubber raft, the radio source is advancing
Therefore, the radio source is moving towards the person at rest down on the rubber raft, therefore, we have;
[tex]f' = \left (\dfrac{v }{v - v_s} \right) \times f[/tex]
(1) Given that (v - [tex]v_s[/tex]) < v, therefore, f' > f, the frequency heard by the person down below floating on the rubber raft, f', is greater (higher) than the frequency produced by the radio
(2) The frequency is not constant as the speed of the source is increasing while it under the acceleration due to gravity
(3) During the fall, the speed of the source continuously increases under the effect of gravitational attraction and therefore the frequency heard by the person on the platform becomes progressively greater (higher)
Explanation:
A commercial jet liner takes off with an average acceleration of 3 g. How long does it take to reach the end of its runway which is 1524 meters away?
Answer:
The time taken for the commercial Jet liner to reach the end of its runway is 10.18 s.
Explanation:
Given;
average acceleration of the commercial Jet liner, a = 3g = 3 x 9.8 m/s² = 29.4 m/s²
distance traveled by the commercial Jet liner, s = 1542 m
The time taken for the commercial Jet liner to reach the end of its runway is calculated as follows;
s = ut + ¹/₂at²
where;
u is the initial velocity of the commercial Jet liner = 0
s = 0 + ¹/₂at²
s = ¹/₂at²
2s = at²
[tex]t = \sqrt{\frac{2s}{a} } \\\\t = \sqrt{\frac{2 \times 1524}{29.4} } \\\\t = 10.18 \ s[/tex]
Therefore, the time taken for the commercial Jet liner to reach the end of its runway is 10.18 s.
A chocolate bar has nutritional energy content of 100KJ. If an 50kg mountain climber eats this chocolate bar and converts it all to potential energy. What altitude(height) can she climb on a mountain using this energy? Consider g=10m/s^2
Answer:
h = 200 m
Explanation:
The energy content of the chocolate is completely converted to the potential energy of the climber. Therefore:
[tex]Energy\ of\ Chocolate = Potential\ Energy\\Energy\ of\ Chocolate = mgh[/tex]
where,
m = mass of climber = 50 kg
Energy of Chocolate = 100 KJ = 100000 J
g = acceleration due to gravity = 10 m/s²
h = height = ?
Therefore,
[tex]100000\ J = (50\ kg)(10\ m/s^2)h\\\\h = \frac{100000\ J}{500\ N}[/tex]
h = 200 m
The distance between two subway stations is 3 miles. If a train travels between the two stations at an average speed of 60 mph, how many minutes does it take for the train to finish the trip between the two stations?
Answer:3 minutes
Explanation:60 miles an hour, 60 minutes in an hour, 1 mile per minute
Pedro is planning to model how changes in weather affect evaporation from lakes. For his first experiment, he wants to test how humidity affects the evaporation rate. He places one beaker with 300 mL of water in a dry area, and he places another beaker with 300 mL of water near a humidifier. Which of the following variables does Pedro need to control during his experiment?
The aim of the experimental model is to test the effect of humidity (changes in weather) on evaporation (rates) from lakes
The control variables in an experiment are the variables that the experimenter intends to keep constant always so as to limit their effect on the measurements of the relationship between the dependent and the independent variable
Therefore in order to have a proper measurement of the effect of humidity on evaporation rate, other variables such as temperature, and the volume of the water in the experiment investigations which affect evaporation rate by the provision of heat, (temperature) and their heat capacity, (the volume and therefore, mass of water) should be controlled
Learn more about controlled variables here;
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Answer: B: Volume of water and temperature
Explanation:
Just took the quiz
Which is one use of lasers
A. reproducing images to make them clearer
B. Producing a magnified image of the moon
C. Cutting an iron bar into two pieces
D. Making a leaf appear larger so it’s veins are visible
Answer:
c
Explanation:
because what else can the laser be used for
Online physics Electrostatic lab
What is generated around the wire where an electric current travels?
Answer:
Whenever current travels through a conductor, a magnetic field is generated.
Explanation:
Answer:
Whenever current travels through a conductor, a magnetic field is generated.
Explanation:
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The carbon cycle relies on producers and consumers to survive. What is the role of each in the carbon cycle?
I REALLY NEED HELP!!
The velocity of a car increases from +4.0 m/s to +16.0 m/s
in a time period of 4.0 s. What was the average
acceleration?
Answer:
Explanation:
Although we do have an equation for this in terms of one-dimensional motion, it's easy enough just to use the mathematical definition of acceleration:
[tex]a=\frac{v_f-v_0}{t}[/tex] which says, in words, the acceleration of an object is equal to the objects final velocity minus its initial velocity, divided by the change in time. Since everything is given in m and s, our answer will be in m/s/s:
[tex]a=\frac{16.0-4.0}{4.0}[/tex] and
[tex]a=\frac{12.0}{4.0}[/tex] so
a = 3.0 m/s/s
Heat flows into a gas in a piston and work is performed on the gas by its surroundings. The amount of work done is equal to the heat added. In this situation,
Answer:
The Internal energy of the gas did not change
Explanation:
In this situation the Internal energy of the gas did not change and this is because according the the first law of thermodynamics
Δ U = Q - W ------ ( 1 )
Δ U = change in internal energy
Q = heat added
W = work done
since Q = W. the value of ΔU will be = zero i.e. No change
endothermic vs exothermic question. please help!
Answer:
i dont know the answer sir !
Explanation:
Water tends to moderate climate. Why is it warmer in the winter and cooler in the summer in cities located near the ocean or large lakes?
A.Water has a low specific heat and therefore changes temperature faster than most other substances.
B.Water has a low specific heat and therefore changes temperature slower than most other substances.
C.Water has a high specific heat and therefore changes temperature more slowly than most other substances.
D.Water has a high specific heat and therefore changes temperature more quickly than most other substances.
It is warmer in the winter and cooler in the summer in cities because water has high specific heat and therefore changes temperature more slowly than most other substances. The correct option is C.
What is climate?Climate is the average weather over a longer period of time in a particular area. A description of a climate includes details such as the typical temperature in each season, the amount of rainfall, and the amount of sunshine.
Coastal weather tends to be more moderate than continental weather, with fewer hot and cold extremes, because the ocean warms and cools more slowly than the atmosphere.
The majority of rain clouds are produced by ocean evaporation, particularly in the tropics, which affects where wet and dry regions on land are located.
Therefore, the correct option is C. Water has a high specific heat and therefore changes temperature more slowly than most other substances.
To learn more about climate, refer to the below link:
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According to ohms law, as the voltage increases across a 40 ohm resistor what happens to the current, resistors, and resistance
Answer:
As the voltage increases, the current flowing through the circuit increases while the resistance of the resistor remains constant.
Explanation:
Ohm's law states that the current flowing through a circuit is directly proportional to the applied voltage.
V = IR
where;
I is the current
R is the resistance
V is the applied voltage
Based on this law (Ohm's law), as the voltage increases, the current flowing through the circuit increases while the resistance of the resistor remains constant.
Already moving at 8 m/s , wendy pushes yasmine in her sled with a diagonal 300.0 n force. th coefficient of kinetic friction between yasmine's sled and the ground is 0.30. how fast will yasmine be going after wendy pushes him for 15.00m
Answer:
You must exert a force of 4.5 N on a book to slide it across a table.
Explanation:
Another child is on a swing next to the first. This child has a mass of 48 kg and a maximum kinetic energy of 3800 J. What is the velocity of this child?
Answer:12.583m/s
Explanation:
[tex]KE=\frac{1}{2}mv^{2}[/tex]
[tex]3800=\frac{1}{2}(48)v^{2}[/tex]
[tex]\frac{3800}{24}=v^{2}[/tex]
[tex]\sqrt{158.33} = v\\12.583m/s=v[/tex]
5. A boy rides his skateboard 50 meters (m) West. Then he turns around
and goes 20 m East. What is the boy's DISPLACEMENT? *
Answer:
-30 m
Explanation:
50-20 but the direction is going west so it’s negative
How did Shi Huangdi link the new lands of his empire
Answer:
Many things, such as building the Great Wall of China, and building highways.
Explanation:
GIVING BRAINLIEST PLEASE HELP!!
-if you answer correctly ill give you brainliest which will give you 25pts-
Answer:
c
Explanation:
heat is thermal energy transferred from a hotter system while temperature is a measure of the average kinetic energy of atoms or molecules in the system
What voltage is required to move 2A through 5Ω?
Need help please help.
Answer:
below
Explanation:
that is the procedure above
Someone please help me
Answer:
A thesis should be a statement that can be argued.
Explanation:
You want to create a model that conducts electricity. Which material should you use?
A. Glass
B. Plastic
C. Wood
D. Copper
Answer:
D. Copper
Explanation:
Copper has the best electrical conductivity of any metal, except silver. A good electrical conductivity is the same as a small electrical resistance.
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How much voltage is required to run 0.054 A of current through a 15 2
resistor? Use AV = IR.
O A. 0.81 V
O B. 1.2 V
O c. 2.8x10²v
O D. 3.6 x 10-3 v
Answer:
The correct option is (a).
Explanation:
Given that,
Current flowing through the resistor, R = 0.054 A
Resistance of the resistor, R = 15 ohms
We need to find the voltage. We know that, Ohm's law gives the relation between voltage, current and resistance i.e.
V = IR
Put all the values,
[tex]V=0.054 \times 15\\\\V=0.81\ V[/tex]
So, the required voltage is equal to 0.81 volts.
Greg can't remember how tall his 9-month-old niece is. He guesses that she is 100 cm tall. Which of the following is true?
Age (months)
Height (cm)
3 61.1
6 67.8
9 72.3
12 76.1
A.
Based on the data, Greg's guess is reasonable.
B.
Based on the data, Greg's guess is not reasonable.
C.
Based on the data, Greg's niece should be around 61.1 cm tall.
D.
Based on the data, Greg's niece should be around 76.1 cm tall.
Answer:
C
Explanation:
Determine whether the interference is constructive or destructive at each location indicated.
A.constructive or destructive
B. constructive or destructive
C. constructive or destructive
D. constructive or destructive
Answer:
A. Constructive
B. Destructive
C. Destructive
D. Constructive
Explanation:
Constructive interference takes place at locations along the path of two superposed waves where the waves are in phase such that a high or low point of one of the waves corresponds with a high or low point of the other wave which gives a resulting wave amplitude which is the sum of the amplitudes of the individual waves
Destructive interference takes place at locations along the path of two superposed waves where one wave is out of phase with the other wave such that a high or low point of one of the waves coincides with a low or high point of the other wave respectively thereby cancelling the effect of the other wave and giving a resulting wave that has an amplitude which is the difference in the amplitudes of the individual waves
Therefore;
At point A, the peak of each wave partially coincides resulting in constructive interference
At point B, the peak of the blue wave and the trough of the red wave partially coincides resulting in destructive interference
At point C, the through of the blue wave and the peak of the back wave partially coincides resulting in destructive interference
At point D, the trough of each wave partially coincides resulting in constructive interference.
Describe how the energy is transferred from the gas hob to cook the egg in the water.
Answer:
remember the ways in which the heat is transferred:
Conduction: Heat transfer of two objects touching.
Convection: Heat transfer in a medium with a gradient of temperature.
Radiation: Heat transferred between two objects that not touch each other (an example of this is how the Sun heats up the Earth)
First, we start with the gas itself.
It has a lot of pressure, so when you open the knob, the gas can get out.
The has chemical potential energy.
When you combust the gas, you transform that energy into heat energy, as the flame touches the pot, it starts o also heat the pot.
This heat energy is transferred to the pot, which transfers heat energy to the water by conduction, the heat in the water is "distributed" by convection, and as the water starts to heat up, the energy is transferred to the egg by conduction.
A typical electromagnetic signal from a communications satellite might have an intensity of 0.600 pW/m2 at the surface of the Earth. Your satellite dish collects the energy of the electromagnetic signal from the satellite; then your dish passes that energy to its central receiver, where the signal can be processed by a circuit. The area of a satellite dish can be calculated from pi (3.1416) times the radius squared. If your satellite dish has a radius of 0.28 m, and if it is receiving the signal described above, how much electromagnetic energy is reflected to the central receiver in 2.5 minutes
Answer:
The answer is "22.05 pJ"
Explanation:
Using formula:
[tex]Energy=power\times time\\\\Power=Intensity \times area[/tex]
Calculating Energy:
[tex]=0.147 \times 2.5 \times 60 \times 10^{-12}\\\\=22.05\ pJ[/tex]
with well labelled diagrams , describe how a bicycle pump works
Explanation:
this is almost similar to how a syringe works. when the pump is drown out, air in the barrel expands and pressure is reduced to below atmospheric pressure. the air from outside the pump is at high pressure so it flows past the leather washer into the barrel. at some point, the higher pressure in the tyre closes for valve.
when the pump handle is pushed in the air is forced into the tyre though the tyre valve which now opens
An object attached to one end of a spring makes 20 complete vibrations in 10s. Its frequency is:
O 2 Hz
.50 s
2 s
.50 Hz
Answer:
0.50 s
Explanation:
principle of quantization of charge
Answer:
Quantization is the process of replacing analog samples with approximate values taken from a finite set of allowed values.
Explanation:
