(a) 646.9 Hz
The formula for the Doppler effect is:
where
f = 600 Hz is the real frequency of the sound
f' is the apparent frequency
v = 345 m/s is the speed of sound
is the velocity of the observer (zero since it is stationary at the station)
is the velocity of the source (the train), moving toward the observer
Substituting into the formula,
(b) 20.1 m/s
In this case, we have
f = 600 Hz is the real frequency
f' = 567 Hz is the apparent frequency
Assuming the observer is still at rest,
so we can re-arrange the Doppler formula to find 
, the new velocity of the train:
and the negative sign means the train is moving away from the observer at the station.
It is 356.5 just subtracts because it’s opposite
Answer:
<h2>The answer is 48 g</h2>
Explanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volume
From the question we have
mass = 2 × 24
We have the final answer as
<h3>48 g</h3>
Hope this helps you
The centripetal force : F = 293.3125 N
<h3>Further explanation</h3>
Given
mass = 65 kg
v = 9.5 m/s
r = 20 m
Required
the centripetal force
Solution
Centripetal force is a force acting on objects that move in a circle in the direction toward the center of the circle
F = centripetal force, N
m = mass, Kg
v = linear velocity, m / s
r = radius, m
Input the value :
F = 65 x 9.5² / 20
F = 293.3125 N
Answer:
The final velocity is 
Explanation:
From the question we are told that
The mass of the child is 
The initial speed of the child is 
The mass of the wagon is 
The initial speed of the wagon is 
The mass of the ball is 
The initial speed off the ball is 
Generally the initial speed of the system (i.e the child , wagon , ball) is
Generally from the law of linear momentum conservation
Here 
is the momentum of the system before the ball is dropped which is mathematically represented as
=> 
=> 
and
is the momentum of the system after the ball is dropped which is mathematically represented as
=> 
So
=>
