Answer:
605 km
Explanation:
Hello
the same units of measure should be used, then
Step 1
convert 42 m/s ⇒ km/h
1 km =1000 m
1 h = 36000 sec
Step 2
find kilometers traveled after 4 hours
V,velocity
s, distance traveled
t. time
now, isolating s
and replacing
S=604.8 Km
Have a great day
Here we can say that rate of flow must be constant
so here we will have
now we know that
now from above equation
so velocity will reduce by factor 0.14
Answer:
The observed frequency by the pedestrian is 424 Hz.
Explanation:
Given;
frequency of the source, Fs = 400 Hz
speed of the car as it approaches the stationary observer, Vs = 20 m/s
Based on Doppler effect, as the car the approaches the stationary observer, the observed frequency will be higher than the transmitted (source) frequency because of decrease in distance between the car and the observer.
The observed frequency is calculated as;
where;
F₀ is the observed frequency
v is the speed of sound in air = 340 m/s
F₀ ≅ 424 Hz.
Therefore, the observed frequency by the pedestrian is 424 Hz.