Average speed is defined as the ratio of total distance covered in total given time

here we know that total distance that man moved is


so total distance is



now here total time of the motion is


total time will be given as


now by above formula


so his average speed is 30 km/h
Answer:
f'=5.58kHz
Explanation:
This is an example of the Doppler effect, the formula is:

Where f is the actual frequency,
is the observed frequency,
is the velocity of the sound waves,
the velocity of the observer (which is negative if the observer is moving away from the source) and
the velocity of the source (which is negative if is moving towards the observer). For this problem:


Answer:
The red ball has a greater kinetic energy, because it has a greater mass
Explanation:
Mass is directly proportional to kinetic energy, as one increases, so does the other
Answer:
Explanation:
separation between two gaps, d = 5 cm
angle between central and second order maxima, θ = 0.52°
use
d Sinθ = n λ
n = 2
0.05 x Sin 0.52° = 2 x λ
λ = 2.27 x 10^-4 m
λ = 226.9 micro metre
Personally, I agree with your answer, namely that the likely-intended event happening here is one of acceleration. Having said that, I also want to add: it pains me to see this type of wording because, clearly, it is vague and only invites confusion of the type you are talking about.
Good luck!