A motorboat starts from rest on a calm lake. Its engine exerts a constant forward thrust. The water exerts a resistive drag force on the boat that is proportional to its speed.
Why does the boat eventually reach a constant maximum speed?
The resistive force decreases until the acceleration of the boat becomes negative.
The resistive force decreases until the acceleration of the boat becomes zero.
The resistive force increases until the acceleration of the boat becomes negative.
The resistive force increases until the acceleration of the boat becomes zero.
183 exam-style questions on CIE IGCSE Physics 1.5.1a Forces, resultant force and motion. Each one has a worked solution and a mark scheme showing where the marks go.