The gravitational force is inversely proportional to the 
square of the distance between their centers.  So the 
force is greatest when the distance is zero.
        
             
        
        
        
Answer:
r₂ = 0.2 m
Explanation:
given,
distance = 20 m
sound of average whisper = 30 dB
distance moved closer = ?
new frequency = 80 dB
using formula
 
    I₀ = 10⁻¹² W/m²
now,
 
 
 
to hear the whisper sound = 80 dB
 
 
 
we know intensity of sound is inversely proportional to square of distances
 
 
 
   r₂ = 0.2 m
 
        
             
        
        
        
Answer: the correct option is B ( on the half of the road that the vehicle is traveling).
Explanation: according to Georgia Code About Pedestrians; The driver must stop and remain stopped to let a pedestrian cross at a crosswalk when the pedestrian is 
on the half of the road that the vehicle is traveling.
 
        
                    
             
        
        
        
Answer:
The first one (60%)
Explanation:
The first one converts 15% more energy than the other one. Therefore, it is more efficient. 
Hope this helps!
 
        
                    
             
        
        
        
The answer is flight technology, satelite technology, and  exploration technology.
The flight technology include advances in jet propulsion and navigation. Satelite have become more and more powerful and hecne communication with distant objects is increasing in efficiency. The emergence of AI robots in space exploration are reducing risks to humans in these deep ventures.