Answer:
The K.E is maximum when the child is at the vertical position and the P.E is maximum at the extreme deviated position from the vertical.
Explanation:
- A child is swinging on swing up and down has both kinetic and potential energy.
- The total mechanical energy of the system is conserved throughout the system. At any instant the total mechanical energy is given by,
                                       E = K.E + P.E
- The K.E is maximum when the child is at the vertical position.
- The P.E is maximum at the extreme deviated position from the vertical.
- And when K.E is maximum P.E becomes minimum and vice versa as per the law of conservation of energy.
 
        
             
        
        
        
The mass needed at peg 1 is a 5g mass.
The 15g should hang at peg 5.
The reason is force x distance clockwise is equal to force x distance anti-clockwise
        
             
        
        
        
The ironwood will because it it more heavy and the others are not 
The higher the amount is the more possible it is to sink
Hope this helped