Answer:
is 3 and 2
Explanation: the firth one is 3 and the 2
This is for the reason that individuals are not continually taking a gander at precisely the same, and on the grounds that individuals' psyches of ten work distinctively and process data in marginally extraordinary ways getting diverse understandings of similar information.
Answer:
An echo is formed as a result of reflection of the original sound which returns to the listener. You might have experienced Echo in an EMPTY ROOM but no echo is produced after the room is occupied. To avoid echo from being produced the echo has to be absorbed.
Explanation:
Answer:
1. it helps to change the direction.
2. it helps us to walk on ground.
3. it helps the vechils to break while moving.
4. helps in changing one form of enegry to another form. eg when we rub our hands we feel heat energy.
5. it opposites the force.
6. it helps us to change shape of objects.eg we roll the dough to make it roti.
7. it changes the state of body from rest motion.eg when we push any obj from inclined plane it moves.
i all know is just 7..
As the question is about changing in frequency of a wave for an observer who is moving relative to the wave source, the concept that should come to our minds is "
Doppler's effect."
Now the general formula of the Doppler's effect is:
-- (A)
Note: We do not need to worry about the signs, as everything is moving towards each other. If something/somebody were moving away, we would have the negative sign. However, in this problem it is not the issue.
Where,
g = Speed of sound = 340m/s.
= Velocity of the receiver/observer relative to the medium = ?.
= Velocity of the source with respect to medium = 0 m/s.
= Frequency emitted from source = 400 Hz.
= Observed frequency = 408Hz.
Plug-in the above values in the equation (A), you would get:
Solving above would give you,
= 6.8 m/s
The correct answer = 6.8m/s