These are digital signals.
Answer:
Change, or increase, the buoyant force.
Explanation:
As the salt water of the sea is denser than the river's fresh water, the boat will rise when entering the sea from the river and sink (to increase the buoyant force) when entering the river from the sea.

The Gravitational Force between given objects will be ~

We know that ~

where ~
= mass of 1st object = 70 kg
= mass of 2nd object = 2000 kg
- G = gravitational constant =

- r = distance between the objects = 1 m
Let's calculate the force ~
It would be accelerating at -9.8 m/s^2 so it’s velocity would be equal to -9.8•1.1 so the answer is 10.78m/s