Answer:
It would be (a)
Explanation:
A theory is something that can be proved through rigorous and repeated experimentation, while choice (b) sounds tempting i believe it fails at the fact that it says that a theory is an "agreement", sure an agreement could be reached by while trained scientists but that does not necessarily mean that what the scientists agree upon is rigorously tested and repeatable, and so therefore cannot be assumed
That is what I think 
Hope this helps :)  
 
        
             
        
        
        
Answer:
7kgm/s
Explanation:
Using the law of conservation of momentum which states that the sum of momentum of bodies before collision is equal to the sum of the bodies after collision.
Let P1A and P1B be the initial momentum of the bodies A and B respectively 
Let P2A and P2B be the final momentum of the bodies A and B respectively after collision.
Based on the law:
P1A+P2A = P1B + P2B
Given P1A = 5kgm/s
P2A = 0kgm/s(ball B at rest before collision)
P2A = -2.0kgm/s (negative because it moves in the negative x direction)
P2B = ?
Substituting the values in the equation gives;
5+0 = -2+P2B
5+2 = P2B
P2B = 7kgm/s
 
        
             
        
        
        
∑F = ma = (90 kg)(1.2 m/s²) = 108 N = 100 N (1 significant digit)
        
                    
             
        
        
        
Answer:
The answer to your question is:
a) 2.7 m/s²
b) -3.6 m/s²
Explanation:
Data
mass of the toolbox = 3.2 kg
a = ?
F = 40 N and F = 20 N
g = 9.81 m/s²
Formula
Second law of motion = F = ma
                               a + g = F / m
                               a = F/m - g
a)                            a = 40/3.2 - 9.81 
                               a = 2.69 ≈ 2.7 m/s²   positive up
b)                            a = 20/ 3.2 - 9.81 
                               a = 6.25 - 9.81 
                                   = - 3.56 ≈ - 3.6 m/s²  negative down