Assuming no other forces are acting on the wheelbarrow, it must be stationary.
        
                    
             
        
        
        
Explanation:
a) d = ½.a.t²
 200 = ½(4)t²
 200 = 2t²
 t² = 200/2
 t² = 100
 t =√100 = 10 s
b) Vt = a. t
 = 4(10)
 = 40 m/s
c) V av. = d/t = 200/10 = 20m/s
 
        
             
        
        
        
Answer:
 a galaxy observed at a distance of 5 billion light-years
 
        
             
        
        
        
Answer:
 F =  .
.
Explanation:
Gravitational force between two objects of masses  kept at a distance r is given by the formula
 kept at a distance r is given by the formula
F = 
Here , = 2m
 = 2m
           =
 = 
          
Thus , F = 
           F =  .
.
 
        
             
        
        
        
Answer:
14869817.395 m
Explanation:
 =22 microarcsecond
=22 microarcsecond
λ = Wavelength = 1.3 mm
Converting to radians we get

From Rayleigh Criterion

Diameter of the effective primary objective is 14869817.395 m
It is not possible to build one telescope with a diameter of 14869817.395 m. But, we need this type of telescope. So, astronomers use an array of radio telescopes to achieve a virtual diameter in order to observe objects that are the size of supermassive black hole's event horizon.