The only thing we know about so far that can shift wavelengths of light
to longer wavelengths is when the source of the light is moving away
from the observer.
When we look at the light from distant galaxies, the light from them is
always shifted to longer wavelengths than it SHOULD have.
AND ... The farther away from us a galaxy IS, the MORE its light is
shifted to wavelengths longer than it should have.
So far, this indicates to us that the whole universe is expanding.
That's the only way to understand what we see, because that's
the only thing we know of that can shift light to longer wavelengths.
By the way ... The most interesting thing about these observations
and measurements is: When astronomers see this light from distant
galaxies and measure the wavelengths, how do they know how far
the wavelengths shifted ? How do they know what the wavelengths
SHOULD be ?
I'll leave you to read about that in the next few years.
The cliff is 12.71m tall.
Why?
Before solving the problem, we must remember that the phone was dropped, it means that there is no initial velocity, also, the acceleration acting on the phone is the acceleration due to gravity.
So, to find how tall is the cliff, we can use the following equations:


Now that we know the time, we can calculate how tall is the cliff:

Hence, we have that the cliff is 12.71m tall.
Have a nice day!
Answer:
Coulomb's law states that the force between two charged objects varies Explanation: