For each load,  Work = (mass) x (gravity) x (distance .
Bigger load:      Work = (10 kg) x (9.8 m/s²) x (2 m) = 196 joules .
Smaller load:    Work = (5 kg)  x  (9.8 m/s²)  x  (4 m) = 196 joules.
The work required is equal in both cases.
The mass ratio of  2:1  is exactly balanced by 
the height ratio of  1:2 .
        
             
        
        
        
Answer:
a.After  second Mr Comer's speed
 second Mr Comer's speed  
  
b.Distance travelled by Mr.Comer in  seconds
 seconds   
   
Explanation:
a. Lets recall our first equation of motion 
Now we know that  ,
 ,  and
 and 

Plugging the values we have.




Then Mr.Comer's speed after  sec
 sec  
 
b.
Lets find the distance and recall our third equation of motion.

So  distance covered.
 distance covered.
Dividing both sides with 2a we have.

Plugging the values.


So Mr.Comer will travel a distance of  .
.
 
        
             
        
        
        
Explanation:
potential energy =360800J
mass(m)=?
height (h)=25m
g=9.8m/s²
we have
potential energy =360800J
mgh=360800J
m×9.8×25=360800
m=360800/(9.8×25)=1472.653061kg
 
        
                    
             
        
        
        
I am pretty sure the answer is C.