Figure 10 shows the horizontal forces acting on a man swimming in the sea - AQA - GCSE Physics Combined Science - Question 7 - 2018 - Paper 2

As the man increases Force A, Force B, which typically opposes his motion, will need to increase to maintain equilibrium. Until Force B equals Force A, the man will accelerate. Once both forces are equal, he will maintain a higher constant velocity as the resultant force reaches 0 N.

To find the resultant force, we can represent the forces graphically. The 3000 N force acting to the west and the 1000 N force acting to the south can be analyzed using the Pythagorean theorem:

$R = \sqrt{(3000^2 + 1000^2)} = \sqrt{9000000 + 1000000} = \sqrt{10000000} = 3162.28 \, N$

The direction can be found using:

$\theta = \tan^{-1}\left(\frac{1000}{3000}\right) \approx 18.43^\circ \text{ (from the horizontal towards the south)}$

Thus, the resultant force is approximately 3162 N at an angle of about 18.43° south of west.

A vector diagram should represent a horizontal arrow of 3000 N pointing west and a vertical arrow of 1000 N pointing south. Ensure both arrows are drawn to scale, maintaining the same proportion.

As the force to the south on the boat increases, the magnitude of the resultant force will also increase. The direction of the resultant force will shift further towards the south.