Answer:
15 meters
Explanation:
The inicial energy of the ball is just potencial energy, and its value is:
E = m * g * h = m * g * 20,
where m is the ball mass, and g is the value of gravity.
In the moment that the ball strickes the ground, all potencial energy transformed into kinetic energy, and 25% of this energy is lost, so the total energy at this moment will be:
E' = 0.75 * E = 0.75 * m * g * 20 = 15*m*g
This kinetic energy will make the ball goes up again, and at the maximum height, all kinetic energy is transformed back into potencial energy.
So, as the mass and the gravity are constants, we can calculate the height the ball will reach:
E' = m*g*h = 15*m*g -> h = 15 meters
Answer:
Constructive Interference
Explanation:
Constructive Interference occurs when two waves superimpose and make bigger amplitudes.
In constructive interference, the crests of one wave fall on the crests of second wave and the amplitudes add up. The amplitude of the resultant wave is equal to sum of the amplitude of the individual waves. Similarly, the trough of first wave falls on the trough of other wave and they superimpose to create the trough of the resultant wave.
For Example, In the attachment, two waves A and B superimpose and demonstrate Constructive interference to create the wave C.
From the concept of optics on a curvature of a spherical mirror, the proportion for which the focal length is equivalent to half the radius of curvature is fulfilled. Mathematically this is

Here,
f = Focal Length
R = Radius
Rearranging to find the radius we have,

Replacing with our values,
R = 2(13.8cm)
R = 27.6cm
Therefore the radius of the spherical surface from which the mirror was made is 27.6cm
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Answer:
In a chemical reaction, the atoms and molecules that interact with each other are called reactants. ... No new atoms are created, and no atoms are destroyed. In a chemical reaction, reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.
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