Answer:
1960 J
Explanation:
Potential energy is given as the product of mass, height and acceleration due to gravity and expressed as mgh where m represent the mass of the swimmer, g is acceleration due to gravity and h is the height. Since the swimmer has just gone 4 m from the surface, that is the height that potential energy is converted to kinetic energy. This follows the law of transformation of energy since the energy can't be lost but rather transformed from one state to another. Therefore, substituting 50 kg for m, 4 m for h and 9.8 for g we obtain that PE=50*4*9.8=1960 J. Since it's not among the options here, maybe it is option D
A line that's 'normal' to the surface is perpendicular to the surface.
The angle of incidence is the angle between the normal and the light ray ARRIVING at the surface.
The angle of reflection is the angle between the normal and the light ray LEAVING the surface after it's reflected.
The law of reflection says these two angles are equal.
Answer: The color of an image is equal to the color of the item forming the picture. When you have a take a observe your self in a mirror, the color of your eyes would not alternate. The reality that the color is equal is proof that the frequency of light would not alternate upon reflection.
This question concerns the general density of atoms in gasses, liquids, and solids.
Light cannot go through atoms. It can only go through the spaces in between the atoms.
Gasses do not have much density, as their atoms are freely flowing in space. Liquids are slightly more dense, as their atoms flow together. Solids are the most dense, as their atoms are tightly packed and do not generally move.
The beam of light passed through a medium at a normal speed. After passing through that medium, it sped up when going through another medium. When it hit a third medium, it stopped.
The first medium suggests a liquid. The second medium suggests a gas, because the beam speeds up and has a higher velocity than the medium before it. The third medium suggests an opaque solid, as the beam is stopped by this medium.
The answer is D. liquid, gas, opaque solid.
