That element is oxygen. It is also highly volatile since it reacts with other elements and is flammable.
speed of sound wave depends on elasticity of medium and density of medium
it is given by formula

now if wave travel through solid then its speed is maximum while if it travel from gas then its speed is minimum
so initially its speed is given as 4000 m/s and suddenly decrease to 1500 m/s
so here we can say that its medium will change from solid to liquid
<em>so sound will encounter with water </em>
Explanation:
Time = Distance/Speed
= 96km / (30km/h)
= 3.2h. (Or 3 hours and 12 minutes)
Using Coulomb's Law <span>
F = {k(Q1)(Q2)}/r²
Where F =force in Newtons, k = Coulomb constant, Q1 = - Q2=
charge of the objects in Coulumbs, and r is the distance between the objects.
Solving for r:
r = sqrt[{k(Q1)(Q2)}/F]
where k = 8.897 x 10^9 N•m²/C², Q1 = 2.5 C, Q2 = -2.5 C, and
F = -700 N
Note: Negative magnitude of Force indicates attraction.
<span>r = 8,912.77 m</span></span>