Answer:
They are the same element. 
Explanation:
Atom >>>>> Proton >>>> Neutron 
A >>>>>>>> 8 >>>>>>>>> 10
B >>>>>>>> 8 >>>>>>>>> 12
From the table above we can see that both atoms have the same proton number. 
Therefore, they are the same element because they have the same proton number which means that they have the same atomic number. The element in this case is existing as an isotope in that the atoms have the same proton number but different neutron number. 
 
        
             
        
        
        
Answer:
The gravity on this planet is stronger than that of earth.
Explanation:
First we need to find the acceleration due to gravity value of this planet to compare its gravity force with that of the earth. Hence, we will use second equation of motion:
h = Vi t + (0.5)gt²
where,
h = height or depth of crater = 100 m
Vi = Initial Velocity of rock = 0 m/s
t = time = 4 s
g = acceleration due to gravity on this planet = ?
Therefore,
100 m = (0 m/s)(4 s) + (0.5)(g)(4 s)²
g = (200 m)/(16 s²)
g = 12.5 m/s²
on earth:
ge = 9.8 m/s²
Since, 
ge < g
Therefore,
<u>The gravity on this planet is stronger than that of earth.</u>
 
        
             
        
        
        
Hello! mark me brainliest please 
The average speed of an object is defined as the distance traveled divided by the time elapsed. Velocity is a vector quantity, and average velocity can be defined as the displacement divided by the time.
        
                    
             
        
        
        
The amount of work done by two boys who apply 200 N of force in an unsuccessful attempt to move a stalled car is 0.
Answer: Option B
<u>Explanation:
</u>
Work done is the measure of work done by someone to push an object from its present position. We can also define work done as the amount of forces needed to move an object from its present position to another position. So the amount of work done is directly proportionate to the product of forces acting on the object and the displacement of the object.  
            
So in this present case, as the two boys have done an unsuccessful attempts to push a stalled car so that means the displacement of the car is zero as there is no change in the position of the car. But they have applied a force of 200 N each. So the amount of work done will be
            
Thus, the amount of work done by two boys will be zero due to their unsuccessful attempt to move a stalled car.