Answer:
I think it's C - sorry if I'm wrong
Answer:
height = 45 m
Explanation:
Initial velocity = 0 m/s
Final velocity = 30 m/s
Acceleration due to gravity = +10m/s^2 ( because ball is going down )
Using the eqn of motion

where v= final velocity ; u = initial velocity ; g = acceleration due to gravity ; h = height
So,



To solve this problem we will apply the concepts related to the 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. Mathematically it can be described as

Here,
=frequency received by detector
=frequency of wave emitted by source
=velocity of detector
=velocity of source
v=velocity of sound wave
Replacing we have that,


Therefore the frequencty that will hear the passengers is 422Hz
Answer:
At a constant speed
Explanation:
If a car is going 30 mph and it isnt going faster or slower, it is not accelerating but it is still moving