Answer:E
Explanation:
This can be explained by Doppler effect which gives the relation between apparent Frequency and actual frequency when the source of sound is moving
where 
here 
as observer is standing
when Ambulance is approaching then velocity of sound and velocity of ambulance have relative velocity thus denominator is less than and apparent frequency is more while when ambulance is going away then velocity of sound waves and velocity of observer is in opposite direction thus denominator is less than 1 and apparent frequency is less.
Thus 
Solids have molecules that move slowly and are close together and are very attracted to eachother.
Liquids have molecules that move freely and are slightly attracted to eachother.
Gases have molecules that move, but aren't attracted to eachother.
Answer:
sorry but I can understand the question
Answer:
Explanation:
In this problem we have three important moments; the instant in which the ball is released (1), the instant in which the ball starts to fly freely (2) and the instant in which has its maximum height (3). From the conservation of mechanical energy, the total energy in each moment has to be the same. In (1), it is only elastic potential energy; in (2) and (3) are both gravitational potential energy and kinetic energy. Writing this and substituting by known values, we obtain:
Since we only care about the velocity 
, we can keep only the second and third parts of the equation and solve:
So, the speed of the ball just after the launch is 17.3m/s.
The correct answer for the mean would be 8
I hope that this helps !
