Answer:
Wavelength can always be found by measuring the distance between any two corresponding points on adjacent waves. In the case of a longitudinal wave, a wavelength measurement is made by measuring the distance from a compression to the next compression or from a rarefaction to the next rarefaction.
Explanation:
Are you referring to the fact that water is a compound while hydrogen is an element? If I'm wrong just comment and clarify and I can edit it, I don't even know what kind of unit you're in. :)
Answer:

Explanation:
consider the mass of each train car be m
m₁ = m₂ = m₃ = m
speed of the three identical train
u₁ = u₂ = u₃ = 1.8 m/s
m₄ = m u₄ = 4.5 m/s
m₅ = m u₅ = 0 (initial velocity )
final velocity
v₁ = v₂ = v₃ = v₄ = v₅ = v
using conservation of momentum
m₁u₁ + m₂u₂ + m₃u₃ + m₄u₄ + m₅u₅ = m₁v₁ + m₂v₂ + m₃v₃ + m₄v₄ + m₅v₅
m (1.8 + 1.8 + 1.8 +4.5) = 5 m v


Wavelength = speed / frequency
(345 m/s) / (20,000 Hz) = 0.017 m
The vertical component of the velocity after the given time is -9.8 m/s while the horizontal component of the velocity is 16 m/s.
The given parameters;
- initial horizontal velocity, vₓ = 16 m/s
- initial vertical velocity,

- time interval 1 seconds
The components of the velocity can be horizontal or vertical velocity.
The vertical component of the velocity is affected by acceleration due to gravity while the horizontal component of the velocity is not affected by gravity.
The vertical component of the velocity is calculated as;

The horizontal component of the velocity is constant since it is not affected by gravity.
The horizontal component of the velocity = 16 m/s
Thus, the vertical component of the velocity after the given time is -9.8 m/s while the horizontal component of the velocity is 16 m/s.
Learn more here:brainly.com/question/20349275