A music fan at a swimming pool is listening to a radio on a diving platform. The radio is playing a constant- frequency tone whe
1 answer:
Answer:
The Doppler Effect is given by the following relation;
Where;
f' = The frequency the observer hears
f = Actual frequency of the wave
v = The velocity of the sound wave
= The velocity of the observer
= The velocity of the source
Where the observer is stationary, we have;
(i) When the source is moving in the direction of the observer
(ii) When the source is receding from the observer, we have;
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;
(1) Given that (v + ) > v, therefore, v < (v +
), 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;
(1) Given that (v - ) < 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:
You might be interested in
Answer:
so the speed will increase by 1.44 times then the initial speed if the distance is increased to double
Explanation:
As we know that the air friction or resistance due to air is neglected then we can use the equation of kinematics here
since we released it from rest so we have
so here we have
now if the distance is double then we have
now from above two equations we can say that
so the speed will increase by 1.44 times then the initial speed if the distance is increased to double
To solve for force, you need to get the product of mass and acceleration.
F = ma
Your given is:
m = 150g
a = ?
v = 50 m/s
t = 20ms
As you can see, you do not have acceleration yet. But if you read the problem you can come up with the formula of acceleration.
Acceleration is the change in velocity over a period of time.
a = change in velocity/time
To get the change in velocity, you get the difference between the initial velocity and final velocity:
The ball was moving initially at a velocity of 50 m/s and it came to a stop. This is your clue. If a ball comes to a stop then that means that the final velocity of the ball is 0 m/s.
So we can put it into our formula now:
WAIT! As you can see, the units do not match. We have ms and s into our equation and that means you cannot proceed till they are the same. First we need to convert ms to s.
x 
= 
So your new time is 0.02s. Now we put this time into the formula:
As you can see our acceleration is a negative value, this indicates that it decelerated or slowed down which makes sense because it was brought to a stop.
So now we have our acceleration. Now using this, we can get our force.
Before we start doing this, you need to take note that the unit of force is N, but when you expand it, it is
but as you can see our mass given is in grams. So again, before you put them into the equation we need to change it into kg first.
Our new mass is 0.150kg.
To make things clearer, let us write down all our new values:
m = 0.150kg
a = -2,500
Now that all our units match, we can put that into our formula:
The value again is negative because it is going against the initial direction of the ball. But if your instructor just wants to get the value of force or the magnitude of the force, just disregard the sign.
F = ma
Your given is:
m = 150g
a = ?
v = 50 m/s
t = 20ms
As you can see, you do not have acceleration yet. But if you read the problem you can come up with the formula of acceleration.
Acceleration is the change in velocity over a period of time.
a = change in velocity/time
To get the change in velocity, you get the difference between the initial velocity and final velocity:
The ball was moving initially at a velocity of 50 m/s and it came to a stop. This is your clue. If a ball comes to a stop then that means that the final velocity of the ball is 0 m/s.
So we can put it into our formula now:
WAIT! As you can see, the units do not match. We have ms and s into our equation and that means you cannot proceed till they are the same. First we need to convert ms to s.
So your new time is 0.02s. Now we put this time into the formula:
As you can see our acceleration is a negative value, this indicates that it decelerated or slowed down which makes sense because it was brought to a stop.
So now we have our acceleration. Now using this, we can get our force.
Before we start doing this, you need to take note that the unit of force is N, but when you expand it, it is
Our new mass is 0.150kg.
To make things clearer, let us write down all our new values:
m = 0.150kg
a = -2,500
Now that all our units match, we can put that into our formula:
The value again is negative because it is going against the initial direction of the ball. But if your instructor just wants to get the value of force or the magnitude of the force, just disregard the sign.