Answer:9.75 m/s
Explanation:
Given
Length of ladder 
Foot the ladder is moving away with speed of 
From diagram 
------1
at 


Now differentiating equation 1 w.r.t time




negative indicates distance is decreasing with time
 
        
             
        
        
        
-- volume = (length)(width)(height)
-- Since the cube is a cube, its three dimensions are all the same number.
Volume = (2.5cm)(2.5cm)(2.5cm)
Volume = 15.625 cubic cm
-- density = (mass) / (volume)
Density = (1129.56g) / (15.625cm^3)
Density = 72.3 g/cm^3
(roughly 3.2 TIMES the density of the most dense naturally occurring substance on Earth)
 
        
             
        
        
        
Answer:
x = 727.5 km
Explanation:
With the conditions given using trigonometry, we can find the tangent
        tan θ = CO / CA
With CO the opposite leg and CE is the adjacent leg which is the distance from the Tierral to Sun 
     
         D =150 10⁶ km (1000m / 1 km)
         D = 150 10⁹ m.
We must take the given angle to radians.
        1º  = 3600 arc s  
        π rad = 180º
        θ = 1 arc s (1º / 3600 s arc) (pi rad / 180º) =
        θ = 4.85 10⁻⁶ rad
That angle is extremely small, so we can approximate the tangent to the angle
      
        θ = x / D
        x = θ D
        x = 4.85 10-6  150 109
        x = 727.5 103 m
        x = 727.5 km
 
        
             
        
        
        
Answer:
I would use the model of Ammonia because it helps you visualize the structure of NH3 better than the description. It would be easier to understand the structure of it if you can see it, rather than reading its description.