The initial kinetic energy of the boat and its rider is

After Sam stops it, the final kinetic energy of the boat+rider is

because its final velocity is zero.
For the law of conservation of energy, the work done by Sam is the variation of kinetic energy of the system:

where the negative sign is due to the fact that the force Sam is applying goes against the direction of motion of the boat.
Answer:
3.16 ×
W/
Explanation:
β(dB)=10 × 
=
W/
β=55 dB
Therefore plugging into the equation the values,
55=10
})[/tex]
5.5=
})[/tex]
= 
316227.76×
= I
I= 3.16 ×
W/