SPM 2010 question.

9. a) weight = force/area
    b) 1. - The weight of the father is heavier than the boy.
            - The volume of water displaced by the father is more than the boy.
            - The buoyant force act on the father is more than the boy.
        2. - When the water displaced increase, the buoyant force increases.
            - When the weight of water displaced increases, the buoyant force also increases.
        3. - Archimede's Principle.
    c) -When the wooden block is submerged in water, the buoyant force is greater than its weight.
        - Hence the buoyant force puches the block upwards.
        - This occurs until the block reaches the surface when the weight of water displaced, the buoyant force 
           decreases and becomes equal to the weight of the block causing it to float.
   d) 1. Streamline shape- to reduce water friction.]
       2. Light material - use light material like bamboo to make it float.
       3. Large size raft - so it is easier to accommodate participants.
       4. Tie the bamboo - tie the bambooin layers. Put motor at the end of the raft to increase the speed of the 
           raft.