Questions Diagram is attached below
Answer:

Explanation:
From the question we are told that:
Speed of Train 
Angle 
Height of window 
Width of window 
The Horizontal distance between B and A from Trigonometric Laws is mathematically given by
  
  
Therefore
Distance from A-A
  
  
Therefore 
Time Required to travel trough d is mathematically given as
  
  
  
 
        
             
        
        
        
Answer:
1.30
Explanation:
To calculate the critical angle we have ti use the formula:

where theta_c is the critical angle, n1 is the index of refraction of the material where the light is totally reflected, and n2 is the refractive index of the other material.
By taking n_2 and replacing we obtain:

hope this helps!!
 
        
             
        
        
        
Answer:
so initial speed of the rock is 30.32 m/s
correct answer is b. 30.3 m/s
Explanation:
given data 
h = 15.0m 
v = 25m/s 
weight of the rock m = 3.00N  
solution
we use here work-energy theorem that is express as here 
work = change in the kinetic energy    ..............................1
so it can be written as 
work = force × distance     ...................2
and 
KE is express as 
K.E = 0.5 × m × v²  
and it can be written as 
F × d = 0.5 × m × (vf)² - (vi)²      ......................3 
here 
m is mass and vi and vf is initial and final velocity 
F = mg = m  (-9.8)  , d = 15 m and v{f} = 25 m/s
so put value in equation 3 we get 
m  (-9.8) × 15 = 0.5 × m × (25)² - (vi)² 
solve it we get 
(vi)² =  919 
vi = 30.32 m/s
so initial speed of the rock is 30.32 m/s
 
        
             
        
        
        
Answer:
1,1 m
Explanation:
Dado que;
coeficiente de fricción = 0,6
sabemos que W = R = mgcos 37 = 3.5Kg * 10m / s ^ 2 * cos37 = 27.95 N
coeficiente de fricción = fuerza / reacción normal (R)
Fuerza = 0.6 * 27.95 N
Fuerza (F) = 16.77 N
Recuerda que F = Ke
dónde;
K = constante de fuerza (15N / m)
e = extensión (lo desconocido)
e = F / K
e = 16,77 N / 15 N / m
e = 1,1 m