Chapter 3, Problem 78GP

Predict/Calculate Suppose we orient the x axis of a two-dimensional coordinate system along the beach at Waikiki, as shown in Figure 3-50. Waves approaching the beach have a velocity relative to the shore given by ${\stackrel{\to }{\text{v}}}_{\text{ws}}=\left(-1.3\text{ m/s}\right)\hat{\text{y}}$. Surfers move more rapidly than the waves, but at an angle θ to the beach. The angle is chosen so that the surfers approach the shore with the same speed as the waves along the y direction. (a) If a surfer has a speed of 7.2 m/s relative to the water, what is his direction of motion θ relative to the beach? (b) What his the surfer’s velocity relative to the wave? (c) If the surfer’s speed is increased, will the angle in part (a) increase or decrease? Explain.