Answer:
993.52 Hz
Explanation:
The frequency of sound emitted by the stationery train is 1057 Hz.
The car travels away from the train at 20.6 m/s.
The frequency the observer hears is given by the formula:

where v = velocity of sound = 343 m/s
vo = velocity of observer
f = frequency from source
This phenomenon is known as Doppler's effect.
Therefore:

The frequency heard by the observer is 993.52 Hz.
Answer:
1531 m
Explanation:
The motion of the jet ski is an uniformly accelerated motion, so we can find the distance travelled by using the following suvat equation:

where
s is the distance
u is the initial velocity
t is the time
a is the acceleration
For the jet ski in this problem,

t = 35 s
u = 0 (it starts from rest)
Solving for s, we find the distance travelled:

Answer: I believe his brother, Mike, who is 6'2, will have the longer shadow.
The answer would be "mechanical". Hope I helped. :)