Answer:
A physical change is a change to the physical—as opposed to chemical—properties of a substance. They are usually reversible. The physical properties of a substance include such characteristics as shape (volume and size), color, texture, flexibility, density, and mass.
The answer to this is A. this is because, refraction with a light or sound wave changing its direction involve propagation,(in which propagation is the change in direction of a light or sound wave)
Answer:
Angular acceleration, is 
Explanation:
Given that,
Initial speed of the drill, 
After 4.28 s of constant angular acceleration it turns at a rate of 28940 rev/min, final angular speed, 
We need to find the drill’s angular acceleration. It is given by the rate of change of angular velocity.
So, the drill's angular acceleration is .
If the energy transfer diagram created by Ray has error in it, it can be corrected by applying the principle of energy conservation.
<h3>What is energy diagram?</h3>
Energy diagram is sketch of the energy flow process or energy transfer or energy conversion process.
The law of energy conservation states that, energy can neither be created nor destroyed but can be converted from one form to another.
Thus, if the energy transfer diagram created by Ray has error in it, it can be corrected by applying the principle of energy conservation.
Learn more about energy conservation here: brainly.com/question/24772394
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