<u>B</u> option is correct .
To develop this problem we will apply the considerations made through the concept of Doppler effect. The Doppler effect is the change in the perceived frequency of any wave movement when the emitter, or focus of waves, and the receiver, or observer, move relative to each other. At first the source is moving towards the observer. Than the perceived frequency at first
Where F is the actual frequency and v is the velocity of the ambulance
Now the source is moving away from the observer.
We are also so told the perceived frequency decreases by 11.9%
Equating,
Solving for V,
Answer:
Final energy will be 40 KJ
Explanation:
We have given that 30 KJ of the heat is transferred to the water
So
And 5 KJ of heat is lost to the surrounding air
So
So total heat
The paddle-wheel work amounts to 5000 N -m
So work done W = -5 KJ ( as work is done by the paddle wheel )
We know that
We have given initial kinetic energy = 10 KJ
So
So final energy = 30+10 =40 KJ
Answer:
6m/s
Explanation:
a = (v-u)/t
acceleration, a
initial velocity, u
final velocity, v
time, t
substitute values and you'll get the answer
The answer should be A because it’s frequency of a sound per second