Asmall ferryboat is 3.90 m wide and 6.30 m long. when a loaded truck pulls onto it, the boat sinks an additional 5.00 cm into the river. what is the weight of the truck?

When the truck's weight is added to the boat, the boat sinks 5 cm deeper,
and displaces additional water whose weight is equal to the weight of the
truck.

The volume of the additional displaced water is

             (3.9 m) x (6.3 m) x (5.0 cm)

         =  (3.9 m) x (6.3 m) x (0.05 m)  =   1.2285 m³ .

The weight of that much water is the weight of the truck.

          Mass of 1 liter of water  =  1 kilogram

          1.2285 m³  =  1,228.5 liters  =  1,228.5 kg of water.

          Weight = (mass) x (gravity)

                      = (1,228.5 kg) x (9.8 m/s²)  =  12,039 Newtons.

                                                                  (about 2,708 pounds) 

Centrapedial force is the answer