Answer:

Explanation:
The relationship between the refractive index and the critical angle is given as follows:

where,
η = refractive index = 1.67
θc = critical angle =?
Therefore,


Answer:
The speed of the skier after moving 100 m up the slope are of V= 25.23 m/s.
Explanation:
F= 280 N
m= 80 kg
α= 12º
μ= 0.15
d= 100m
g= 9,8 m/s²
N= m*g*sin(α)
N= 163 Newtons
Fr= μ * N
Fr= 24.45 Newtons
∑F= m*a
a= (280N - 24.5N) / 80kg
a= 3.19 m/s²
d= a * t² / 2
t=√(2*d/a)
t= 7.91 sec
V= a* t
V= 3.19 m/s² * 7.91 s
V= 25.23 m/s
Position is measured in meters (m), so it is a base quantity.
<h3>What is base quantity?</h3>
A base or fundamental quantity is a physical quantity, in which other quantities are derived from.
Example of fundamental quantities;
- Mass
- Length (position)
- Time
- Temperature
- Amount of substance
<h3>What is a derived quantity?</h3>
Derived quantities are those quantities obtained or expressed from fundamental quantities.
Example of derived quantities;
- Speed
- Acceleration
- Volume
- Area
- Density, etc
Thus, we can conclude that position measured in meters (m) is a base quantity.
Learn more about base quantities here: brainly.com/question/14480063
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It's a hardness scale from 1-10 determining how easy or hard it is to scratch the mineral.
Remember that talc (like chalk or baby powder) is the softest and easiest to scratch then diamond being 10 is the hardest mineral to scratch or break or cut