If a boat and its riders have a mass of 900 kg and the boat drifts in at 1.4 m/s how much work does sam do to stop it?

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.

Pretty sure the answer is b : )

Ais the