These are more of ideas to help your brain invent something less chessy...
Erosion is like corrosion, with no acid.
Erosion happens 'cuz the surface get frozen and beaten by the ocean. (they kinda rhyme) :)
Erosion is the transportation of, the deportation...
~OR~
I cant think of anything for weathering but i got something good, but its still cheesy/ ):
Erosions' got the grooves and so it moves. But weathering breakdown and changes so its molecules changes.
I'm sorry these kinda suck...
Explanation:
It is given that,
Frequency of the laser light, 
Time,
(a) Let
is the wavelength of this light. It can be calculated as :



or

(b) Let n is the number of the wavelengths in one pulse. It can be calculated as :


n = 13440
Hence, this is the required solution.
The mean may be calculated by summing the values of the refractive index and dividing the sum by the number of experiments. This is:
Mean = (1.45 + 1.56 + 1.54 + 1.44 + 1.54 + 1.53)/6
Mean = 1.51
The mean absolute error is the sum of the absolute values of errors divided by the number of trials:
MAE = (|1.45-1.51|+|1.56-1.51|+|1.54-1.51|+|1.44-1.51|+|1.54-1.51|+|1.53-1.51|)/6
MAE = 0.043
The fractional error is the MAE divided by the actual value:
Fractional error = 0.043 / 1.51
Fractional error = 43/1510
The percentage error is the fractional error multiplied by 100:
Percentage error = 2.85%
Using the Universal Gratitation Law, we have:
Again applying the formula in the new situation, comes:
Number 4If you notice any mistake in my english, please let me know, because i am not native.