The required value of the index of refraction of glass is 1.5.
Given data:
The speed of light in a vacuum is, .
The speed of light in a glass is, .
Light has the tendency to travel from one medium to another, then the difference between the speeds of light in various mediums is determined by a term, known as the index of refraction. The mathematical expression for the index of refraction of glass is,
n = c / v
Solving as
Thus, we can conclude that the required value of the index of refraction of glass is 1.5.
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Answer: option 1. thermal expansion and contraction.
The thermostat uses the thermal expansion and contraction of metals: when the metal expands it acts as a switch, a coiled ribbon expands and the electric circuit is off, then the current stops. When the temperatures decrease, the coiled ribbon contracts and the circuit is on, then the current starts to flow and the resistance starts to radiate heat.
The gazelle has zero average acceleration because it's moving at a constant speed. Constant speed means no change in speed means zero acceleration.
The cheetah, on the other hand, changes its speed from 0 m/min to 1820 m/min in a matter of 3 seconds, so its average acceleration is
a[ave] = (1820 m/min - 0 m/min) / (3 s)
… = (1820 m/min) / (3/60 min)
… = 36,400 m/min²
… = (36,400 m) / (60 s)²
… = 91/9 m/s² ≈ 10.1 m/s²
Answer: U = 120 m/s
v = 0
t = 0.01 s
a = (v-u)/ t = -120 / 0.01 = -12000 m/s
a) S = (v² - u²)/2a = -120² / 2*(-12000) = 120 / 200 = 0.6 m
distance of penetration is 0.6m
b) force = ma = 0.005×12000 = 60N