Between centre of curvature and principal focus.
<span><u>Answer </u>
A). Absorption
<u>Explanation
</u>
Sound travels inform of waves. Waves have certain properties. They can be reflected, diffracted refracted, they can also be absorbed. Some materials such as cotton and other soft materials absorbs wave sounds. When this waves are absorbs sound cannot be heard.
For this reason, houses with carpet are much quieter because carpet absorbs sound wave better than hardwood, and tiles.
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Answer:

Explanation:
Given the absence of non-conservative force, the motion of the coin is modelled after the Principle of Energy Conservation solely.



The moment of inertia of the coin is:

After some algebraic handling, an expression for the maximum vertical height is derived:




Answer:
17.71N/m
Explanation:
The period of the spring is expressed according to the expression;

m is the mass of the object
k is the force constant
Given
m = 5.50kg
T = 3.50s
Substitute into the formula;

Hence the force constant of the spring is 17.71N/m
The law applied here is Newton's first law, also known as, law of inertia.
This law states that: A body will retain its state of rest or motion unless acted upon by an external force.
If you are moving and the bus suddenly stops, your body will lurch forward trying to retain its state of motion until it comes to rest and changes its state by the external force acted on it.
If you are at rest and the bus suddenly moves, your body will lurch backwards trying to retain its state of rest and opposing the force of motion until it is forced to change its state by this force.