To solve the exercise it is necessary to take into account the definition of speed as a function of distance and time, and the speed of air in the sound, as well
Where,
V= Velocity
d= distance
t = time
Re-arrange the equation to find the distance we have,
d=vt
Replacing with our values
It is understood that the sound comes and goes across the entire lake therefore, the length of the lake is half the distance found, that is
Therefore the length of the lake is 634,55m
79 m/s. A stone dropped from the top of the Empire State Building will have a velocity of 79 m/s just before it strikes the ground.
This problem is about free fall, to find the velocity of the stone before it strikes the ground we have to use the equation 
, the initial velocity of the stone is 0 m/s. Then:
Solving the equation above with g = 9.8 m/s², and h = 318.0 m:
≅ 79 m/s
True it is a spiral galaxy
The earth has less creators because there is a protective atmosphere which makes the asteroids burn up before they hit the surface of earth. Which means by the moon not having an atmosphere small rocks are easily colliding with the moons surface.
The speed of a wave depends on the medium :)
