Answer:
option B
Explanation:
The correct answer is option B
When the displacement in the harmonic motion is maximum then kinetic energy at the maximum point is minimum and the potential energy is maximum at that point.  
So, when the displacement is maximum, spring force magnitude is also maximum because the force is proportional to the displacement and also the magnitude of the acceleration is maximum so, the net force is also maximum.
 
        
             
        
        
        
Explanation:
time spent to run from house to school=100/5=20s
time spent to return from school=100/10=10s
average velocity=200m/(10+20)
 
        
             
        
        
        
The gravitational pull of Earth is stronger in satellite A
 
        
             
        
        
        
Answer:
the potential energy is 114 J.
Explanation:
Given;
total mechanical energy, E = 400 J
kinetic energy, K.E = 286 J
The potential energy is calculated as follows;
E = K.E +  P.E
where;
P.E is the potential energy 
P.E = E - K.E
P.E = 400 J - 286 J
P.E = 114 J
Therefore, the potential energy is 114 J.
 
        
             
        
        
        
In order to make things easier to describe and explain, let's call 
the resistance of each bulb 'R', and the battery voltage 'V'.
a).  In series, the total resistance is 3R.
In parallel, the total resistance is R/3.
Changing from series to parallel, the total resistance of the circuit
decreases to 1/9 of its original value.
b).  In series, the total current is  V / (3R) .
In parallel, the total current is  3V / R .
Changing from series to parallel, the total current in the circuit
increases to 9 times its original value.
c).  In series, the power dissipated by the circuit is  
                                   (V) · V/3R  =  V² / 3R .
In parallel, the power dissipated by the circuit is 
                                   (V) · 3V/R  =  3V² / R .
Changing from series to parallel, the power dissipated by 
the circuit (also the power delivered by the battery) increases 
to 9 times its original value.