Answer:
Sound is a vibration, or wave, that travels through the air. Sound waves are invisible to our eyes; unless we find a way to make the sound waves move something that we can see. In this activity, your child will use different noise-making objects to cause sound waves and make sand visibly move.
Sound wave can be described by five characteristics: Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed. The minimum distance in which a sound wave repeats itself is called its wavelength.
Explanation:
When the vibrating air hits your eardrum, it causes your eardrum to vibrate, just as the balloon did. These vibrations are transferred through the tiny bones in your ear to the inner ear. These vibrations are detected by nerves, which send impulses that your brain "hears" as sound.
Answer:

Explanation:
The density of an object is given by

where
m is the mass of the object
V is its volume
In this problem,
m = 42 kg
V = 22 m^3
Substituting into the equation, we find the object's density:

In an atom of hydrogen the orbit radius is given by the formula:
r = n² · α₀
where:
n = number of orbit = 15
α₀ = Bohr radius (innermost radius) = 0.529 Â
Since d = 2 · r, we can write:
d = n² · d₀
= 15² · 1.06
= 238.5 Â
Hence, the <span>diameter of the fifteenth orbit of the hydrogen atom is 238.5 </span>Â.
Answer:
The force of gravity does not affect the horizontal component of motion; a projectile maintains a constant horizontal velocity since there are no horizontal forces acting upon it.
Explanation:
Given that,
Mass of the particle, m = 4 kg
Speed of the particle, v = 2.5 m/s
The radius of the circle, r = 2 m
We need to find the angular momentum about the center of the circle. The formula for the angular momentum is given by :

Substitute all the values,

So, the angular momentum of the particle is 20 kg-m² s.