Answer:
Its speed decreases.
Explanation:
When light enters into water, its speed decreases (as well as its frequency). This is the reason why refraction (the bending of light when it changes media) occurs.
This can be proven mathematically.
Given that the refractive index of water is 4/3, we know that refractive index is the ratio of the speed of light in a vacuum to the speed of light in another medium.
Therefore,
4/3 = (speed of light in vacuum) / (speed of light in water)
Speed of light in a vacuum is 3 * 10^8. Hence,
Speed of light in water is:
v = (3 * 10^8) / (4/3)
v = 2.25 * 10^8 m/s
As we can see, the speed of light decreases in water.
Answer:
Explanation:
We will use the KE equation you wrote here and fill in what we are given:
and isolating the m:
which gives us
m = .50 kg
Bob gained (80lbs x 14ft) = 1120 ft-lbs of energy.
Fred gained (110lbs x 14ft) = 1540 ft-lbs of energy
Since they both took the same amount of time, Fred's power (rate
of doing work) was greater than Bob's power (rate of doing work).
