A boat of mass (including the rower) is at rest on still water
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A boat of mass 200kg (including the rower) is at rest on still water. During each stroke the rower’s oars exert an average horizontal force of 300N on the water for 1.5s. The water offers a constant resistive force of 100N on the boat at all times. Between strokes, which last 0.5s, the oars are out of the water and only the resistive force acts.
Answer the following, assuming the forces remain constant and horizontal throughout.
(i) Calculate the magnitude and direction of the net horizontal force on the boat while the oars are in the water.
(ii) Determine the acceleration of the boat during the period the oars are in the water.
(iii) Starting from rest, find the speed of the boat immediately after ten complete strokes.