The impulse required to decrease the speed of the boat is equal to the variation of momentum of the boat:

where
m=225 kg is the mass of the boat

 is the variation of velocity of the boat
By substituting the numbers into the first equation, we find the impulse:

and the negative sign means the direction of the impulse is against the direction of motion of the boat.
 
        
                    
             
        
        
        
Answer: Improvement Invention means any CCIA Invention and CCIA's rights as a joint owner in a Joint Invention that is sufficiently different from the scope of a Licensed Patent to be separately patentable, and covered by the claims of Licensed Patents.
 
        
             
        
        
        
The best frequency should be 70 Hz you simply find the difference between 280 Hz and 210 Hz