Answer:
If there is no resistance, current, wind, or friction on the boat, the boat would keep moving in the same direction at the same speed.
Explanation:
Newton's First Law of Motion suggests that if no external force acts upon an object, that object would continue moving in the same direction at the initial speed.
However, all objects near the surface of the earth (including the boat in this question) experience the effect of gravitational pull (an external force from the earth.) Because of these external forces, Newton's First Law of motion (when phrased in this way) would not apply to the boat.
It is frequently possible to use a more general version of this statement: if the net force on an object is zero, that object would continue moving in the same direction at the initial speed.
In other words, the object would move in the same direction at the initial speed as long as all the external forces on that object balance each other.
Assume that there is no resistance, current, wind, or friction on the boat. After the engine of the boat is turned off, the following would be the forces on this boat:
- downward gravitational attraction from the earth, and
- upward buoyancy from the water, which counteracts the gravitational attraction on the boat.
If the water is sufficiently calm, these two forces would balance one another. The external force on this boat would be zero. Hence, the boat would keep moving in the same direction at the same speed.
