Gravity pulls to the centre of the earth. A ship floats in water because the water pushing it up (upthrust) is equal to the force<span> of gravity (weight) pulling it </span>down<span>. Friction also occurs when objects move through air. This is </span>called<span>air resistance.</span>
Answer: Helium has 2 protons.
Answer:
The frequencies are 
Explanation:
From the question we are told that
The length of the ear canal is 
The speed of sound is assumed to be 
Now taking look at a typical ear canal we see that we assume it is a closed pipe
Now the fundamental harmonics for the pipe(ear canal) is mathematically represented as

substituting values


Also the the second harmonic for the pipe (ear canal) is mathematically represented as
substituting values
Given that sound would be loudest in the pipe at the frequency, it implies that the child will have an increased audible sensitivity at this frequencies
Answer:
The tangential speed of the tack is 6.988 meters per second.
Explanation:
The tangential speed experimented by the tack (
), measured in meters per second, is equal to the product of the angular speed of the wheel (
), measured in radians per second, and the distance of the tack respect to the rotation axis (
), measured in meters, length that coincides with the radius of the tire. First, we convert the angular speed of the wheel from revolutions per second to radians per second:


Then, the tangential speed of the tack is: (
,
)


The tangential speed of the tack is 6.988 meters per second.