1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Cerrena [4.2K]
4 years ago
13

The Doppler effect is an effect produced by a moving source of sound or electromagnetic waves due to the relative motion of a so

urce or a receiver. If an emergency vehicle approaches Bob and moves away from Jill, how does the frequency of the siren change?
Physics
2 answers:
IrinaK [193]4 years ago
8 0

Answer:

Apparent frequency increases for Bob and decreases for Jill.

Explanation:

Doppler effect refers to the apparent change in frequency when there is relative motion between source and the listener. When the source and listener move closer, the apparent frequency heard by the listener increases. And when the source and listener move away from each other, the apparent frequency heard by the listener decreases.

Thus, when the emergency vehicle approaches Bob, the apparent frequency of the siren increases. It moves away from Jill, the apparent frequency  heard by the Jill decreases.

mojhsa [17]4 years ago
5 0

Answer:

change in frequency

You might be interested in
Wolves are a keystone species because they are _____. at the top of the food chain are physically the largest animal in the food
enot [183]

Answer:

Wolves are a keystone species because they are so important to the ecosystem that their removal causes a catastrophic disequilibrium.

Explanation:

Wolves are the predators available in the environment but they exist in relatively less number while comparing it with another species of animals. Wolves influence their pray which are influenced by plants. Thus, They are so important to the ecosystem that their removal causes a catastrophic disequilibrium.

4 0
3 years ago
Read 2 more answers
2. An optical fibre is 1200km long and it takes light 0.006s to travel from one end to the other. Calculate the speed of light i
natita [175]
The average speed <em>appears to be</em> (distance) / (time) =

(length of the cable) / (time from when a pulse goes in until it comes out the other end) .

That's  1,200,000 meters/ 0.006 second  =  2 x 10^8 = <em>2 hundred million m/sec</em>

That figure is about 66.7% of the speed of light in vacuum.

The reason I went through all of this detail was to point out that this is
NOT necessarily the speed of light in this glass, for two reasons.

1).  The path of light through an optical fiber is not straight down the middle.  In the original fibers of 20 or 30 years ago, the light bounced back and forth off the inside walls of the fiber, and zig-zagged its way along the length.  In current modern fibers, it still zig-zags, but it's a more gentle, up-and-down curved path.  In either case, the distance covered by the light inside the fiber is more than the straight length of the cable, and the time it takes it to come out the other end is more than its actual speed inside the glass would have meant if it could have traveled straight through the pipe.

2).  This problem talks about an optical fiber that's 1,200km long.  There is loss in optical fiber, and you're NOT going to get light all the way through a single piece of it that's something like 745 miles long.  It takes electronic repeaters, "boosters", and regenerators every few miles to keep it going, and these devices add "latency" or time delay in the process of going through them.  That delay in the electronics shows up as apparent delay through the fiber-optic cable, and it makes the speed through the glass appear to be slower than it actually is.
6 0
3 years ago
Read 2 more answers
A ball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and pa
VLD [36.1K]

The ball takes 0.2 sec to travel the height of the window, which is 2 m.

 Then the speed of the ball at that time was

v = \frac{d}{t}

v = \frac{2}{0.20}

v = 10\ \frac{m}{s}

We know that:

v = v_0 -gt

Where v_0 is the initial velocity.

So:

10 = v_0 -9.8(2)

10 + 9.8(2) = v_0

v_0 = 29.6\ m / s

Then we have the equation for the position as a function of time.

r = r_0 + v_0t - \frac{1}{2}gt^2

Where

r_0 = initial position

r = position as a function of time

v_0 = initial velocity

g = acceleration of gravity

t = time.

If the ball is thrown from the ground then:

r_0 = 0 m

We want to find now the distance between the window and the ground.

When the ball reaches the bottom of the window t = 1.8s

So:

r = 0 + 29.6(1.8) - 0.5(9.8)(1.8)^2

r = 37,404 m

The window is 37,404 m high

Finally, to know how high the ball rises we must know at what moment the vertical velocity of the ball is zero.

v = v_0 -gt\\\\0 = v_0 -gt\\\\gt = v_0\\\\t = \frac{29.6}{9.8}

t = 3.02\ s

Now we replace t in the position equation

r = 0 + 29.6(3.02) -0.5(9.8)(3.02)^2

r = 44.70\ m

The ball reaches up to 44.70 m in height.

3 0
4 years ago
What is magnetic shielding?<br>​
AysviL [449]
It is basically shielding a magnetic field. This can be done with rubber or any other material that is thick. Normally small magnets already block the shield.
5 0
2 years ago
If people are going to cut down a tree anyway, what difference does
Dafna11 [192]
Fruit trees are important because they can make more trees from the seeds of their fruit. regular trees just drop leaves and pollen
3 0
3 years ago
Read 2 more answers
Other questions:
  • What is required to cause acceleration
    10·2 answers
  • A bat strikes a 0.145-kg baseball. Just before impact, the ball is traveling horizontally to the right at 35.0 m/s ; when it lea
    15·1 answer
  • Which one of the following are appropriate units for measuring volume?
    5·1 answer
  • There was a groundbreaking court decision in 1783 in massachusetts regarding an escaped slave named ___________ frederick dougla
    13·1 answer
  • The cylindrical tub of a dryer in a laundromat rotates counterclockwise about a horizontal axis at 41.5 rev/min as it dries the
    5·1 answer
  • A monatomic ideal gas expands slowly to twice its original volume, doing 370 j of work in the process. part a find the heat adde
    5·1 answer
  • Why was Bohr’s atomic model replaced by the modern atomic model
    5·2 answers
  • The power of a machine mesures
    14·1 answer
  • A child moving at constant velocity carries a 2 N ice-cream cone 1 m across a level surface. What is the net work done on the ic
    15·1 answer
  • An object falls from a height of 12m. The object's potential energy at the top is 50J. Where is the potential energy of the obje
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!