Answer:
1) 3.1 m/s
2) 7 m/s
Explanation:
Distance due north = 80 m
Distance due south = 30 m
Distance between north and south = (80 - 30) m = 50 m
Total time = (12 + 4) sec = 16 sec
1) Average speed = 50/16 = 3.1 m/s
2) Average velocity = Total distance/total time = (80 + 30) m/16 s = 110/16 = 7 m/s
 
        
             
        
        
        
Displacement is d  
Vf² = Vi² + 2 g d  
(-20²) = (+10²) + 2 (-9.8) d  
-19.6 d = 300  
d = -15.3 m  
negative means lower
time is t  
d = Vi t + 1/2 g t²
-15.3 = 10 t + (-4.9) t²
4.9 t² - 10 t -15.3 = 0  
t = 3.06 s
 
        
             
        
        
        
Land surfaces change, erosion happens, the ground collapses, etc.
        
                    
             
        
        
        
From britaññica it said time and money. They didn’t have either to switch over from the industrial period and never did. Also from my own person reasoning i think most of the world uses not US customary, so to make stuff more accessible. hope this helps!
        
             
        
        
        
Answer:
The cost of energy is $ 0.34. 
Explanation:
The energy is the capacity to do work. 
The energy is a scalar quantity and its SI unit is Joule. 
The commercial unit of energy is kWh. 
Cost of 1 kWh energy = $ 0.17 
energy loss by standard window is 2 kWh . 
So, the cost of lost of energy is 
Cost = $ 0.17 x 2 = $ 0.34