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Anastaziya [24]
2 years ago
9

Have you heard an ambulance, police car, or fire truck recently? Did you notice that the pitch of the siren changed as it approa

ched you and then again as it moved away? What concept explains this change or shift in sound waves?
Physics
2 answers:
Tanzania [10]2 years ago
5 0
The Doppler Effect is the change in frequency or wavelength of a wave for an observer moving relative to its source. It is named after the Austrian physicist Christian Doppler.
Bumek [7]2 years ago
3 0

Answer: Doppler effect

Explanation:

When there is relative motion between source and listener of sound, the apparent frequency heard by the listener is different from the frequency of the source. When the source and the listener are moving closer, the apparent frequency increases and when they move apart, there is decrease in the apparent frequency. This is Doppler's effect.

The wave-fronts move closer as the source and listener approach closer to each other. Thus, the observed frequency is greater than the actual. The pitch depends on frequency, greater is the pitch.

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Which term is defined by the force that moving, charged particles exert on one another?
Lisa [10]

Answer:

Electromagnetic force

Explanation:

There are four fundamental forces in nature:

- Gravity: it is the force that is exerted between any objects with mass. It is the weakest of all forces, so it is only relevant at planetary scales. It is always attractive, and it has an infinite range.

- Electromagnetic force: it is the force exerted between charged objects and between magnets (it is responsible for electric fields and magnetic fields). It is the 2nd strongest force, and it is the force that holds atoms in a molecule together. It can be attractive or repulsive, and it has an infinite range.

- Strong nuclear force: it is the strongest of all forces. It is responsible for holding the nucleons together inside the nucleus, and it is attractive. It has a very limited range (10^{-15}m), so it is relevant only at very small scales

- Weak nuclear force: it is the force responsible for radioactive decays and neutrino interactions. It also has a very short range (10^{-18} m

Looking at all these definitions, we see that the term that defines the force that acts between charged particles is the electromagnetic force.

7 0
3 years ago
Car A, moving in a straight line at a constant speed of 20. meters per second, is initially 200 meters behind car B, moving in t
MA_775_DIABLO [31]
First, let's express the movement of Car A and B in terms of their position over time (relative to car B)
For car A: y=20x-200   Car A moves 20 meters every second x, and starts 200 meters behind car B
For Car B: y= 15x      Car B moves 15 meters every second and starts at our basis point

Set the two equations equal to one another to find the time x at which they meet:
20x - 200 = 15x
200 = 5x 
x= 40
At time x=40 seconds, the cars meet. How far will Car A have traveled at this time? 
Car A moves 20 meters every second:
20 x 40 = 800 meters
8 0
3 years ago
when 10 similar coins are dropped into a graduated cylinder from 75 ml to 100ml. what is average volume of each coin?​
Alex787 [66]

Explanation:

Volume of 10 coins = 100ml - 75ml = 25ml

Volume of 1 coin = 25ml / 10 = 2.5ml

The average volume of each coin is 2.5ml.

8 0
2 years ago
Read 2 more answers
Question 4 of 20
Mnenie [13.5K]

Answer:

D

Explanation:

F = G m1 m2 / r^2       now double  r

 F =  G m1m1/ (2r)^2

    F =  1/4  G m1m2/r^2     <===== this is 1/4 of the original

5 0
1 year ago
A particular heat engine has a mechanical power output of 4.00 kW and an efficiency of 26.0%. The engine expels 8.55 103 J of ex
Ivahew [28]

To develop the problem we will start by finding the energy taken by each cycle through the efficiency of the motor and the exhausted energy. Later the work will be found for the conservation of energy in which this is equivalent to the difference between the two calculated energy values. Finally the estimated time will be calculated with the work and the power given,

\text{Efficiency of the heat engine} = \eta = 26\% = 0.26

\text{Energy taken in by the heat engine during each cycle} = Q_h

\text{Energy exhausted by the heat engine in each cycle} = Q_c = 8.55*10^3 J

\eta = 1 - \frac{Q_{c}}{Q_{h}}

0.26 = 1 - \frac{8.55\ast 10^{3}}{Q_{h}}

\frac{8.55* 10^{3}}{Q_{h}} = 0.74

Q_h = \frac{8.55*10^3}{0.74}

Q_h = 11.554*10^3J

PART A)

Work done by the heat engine in each cycle = W

W = Q_h-Q_c

W = 11.554*10^3J-8.55*10^3J

W = 3004J

According to the value given we have that,

P = 4.0kW

P = 4000W

Power is defined as the variation of energy as a function of time therefore,

P = \frac{W}{t}

4000W = \frac{3004J}{t}

t = \frac{3004}{4000}

t = 0.75s

Therefore the interval for each cycle is 0.75s

5 0
3 years ago
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