A worker is poling a ship across a shallow lake. He pushes parallel to the length of the light pole exerting on the bottom of the lake a force of 235 Newton. Suppose the pole lies in the vertical plane containing the boat's keel. At one moment, the pole creates an angle of 25 degree with the vertical and the water exerts a horizontal drag force of 47.5 Newton on the boat opposite to its forward velocity of magnitude 0.857 m/s. The mass of the ship including its cargo and the workers is 400 kiloigram.
a) The water exerts a buoyant force vertically upward on the ship. Calculate the magnitude of this force.
______ N
b) Model the forces as constant over a short interval of time to calculate the velocity of the ship 0.600 sec. after the moment described.
_______m/s