Answer:
<u>CHEMICAL CHANGE</u>:
A change in which one or more substances are converted into new substances is a <em>chemical change</em>.
<u>EXPLANATION:</u>
Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances.
<u>EXAMPLE:</u>
<em>Examples of Chemical Change in Everyday Life
</em>
Burning of paper and log of wood.
Digestion of food.
Boiling an egg.
Chemical battery usage.
Electroplating a metal.
Baking a cake.
Milk going sour.
Various metabolic reactions that take place in the cells.
Answer:
v=32.9m/s
Explanation:
The acceleration needed to mantain a circular motion of radius r and speed v is given by the equation 
This is the centripetal acceleration. The person will feel what is called a centrifugal acceleration, of the same value, because he is not in an inertial frame (thus subject to fictitious forces, product of inertia).
We want to know the speed of his head when it is subject to 12.5 times the value of the acceleration of gravity while moving on a 8.84m radius circle, so we must do:

the wavelength is to be 56.67 cm and I know that i should be applying the double slit equation for destructive interference.
A solid has a definite meaning that there is only one shape there can be meaning a solid has a definite volume