PRETTY SURE ITS A AND C BUT I LOOKED IT UP AND IM ALMOST POSITIVE THARS IT
Answer:
a)θ=71.89°
b)NO
Explanation:
Given that
For glass n= 1.38
We know that for air n'=1
The angle for total internal reflection θc given as
sin θc=n'/n
By putting the values
sin θc=n'/n
sin θc=1/1.38
θc=46.43°
n'sinθ = n sinθref
sinθref = cosθc
n'sinθ = n cosθc
1 x sinθ =1.38 x cos 46.43°
θ=71.89°
b)
NO
Answer:

Explanation:
v = Orbital speed = 130 km/s
d = Diameter = 16 ly
r = Radius = 
G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²

As the centripetal force balances the gravitational energy we have the following relation

Mass of the the massive object at the center of the Milky Way galaxy is 
Answer:
Explanation:
Using the equation of motion v² = u²+2as
v is the final velocity = 40m/s
u is the iniyail velocity 0m/s
a is the acceleration
s is the displacement
Substituting in the formula;
40² = 0²+2a(50)
1600 = 100a
Divide both sides by 100
100a/100 = 1600/100
a = 16
Hence the car acceleration is 16m/s²
Answer:
This might be because since they reproduce without mating, the genes of their offspring have are not mixed with anyone elses, making them have very little variation in contrast with those that reproduce our way.