Weak winds that blow for short periods of time with a short fetch.
I'm pretty sure it's Inertia and Gravity
Inertia deals with an object's tendency to stay in motion at a constant speed.
Hopefully this helped and good luck.
The answer is D, because the collision's between molecules are elastic, not inelastic.
Answer:

Explanation:
given,
frequency of tuba.f = 64 Hz
Speed of train approaching, v = 8.50 m/s
beat frequency = ?
using Doppler's effect formula

v_s is the velocity of the source
v is the speed of sound, v = 340 m/s
now,

f' = 65.64 Hz
now, beat frequency is equal to



hence, beat frequency is equal to 1.64 Hz