The speed of sound at T=25°C is Vs=346 m/s. So the sound has to reach the cliff and return back to you so the path it needs to travel is s=2*440 m = 880 m.
Since the speed of sound is constant s=Vs*t, and t= s/Vs=880/346=2.54335 s. You will hear the echo after t=2.54335 s after you shouted.
F = ma
a = f/m
if f doubled , acc. will be doubled
In several of the questions you've posted during the past day, we've already said that a wave with larger amplitude carries more energy. That idea is easy to apply to this question.
Loudness of a sound wave is directly proportional to the intensity of the sound wave. In other words, when one increases, other also increases and vice-versa
Hope this helps!
