A ferry boat crosses a river and arrives at a point on the opposite bank directly across from its starting point. The boat can travel at 4 m/s and the current is 1.5 m/s. If the river is 650 rn wide at the crossing point, in what direction must the boat steer and how long will it take to cross?
its speed toward the opposite bank is
√(4^2 - 1.5^2) = 3.7 m/s
so it will take 650/3.7 = 175.3 seconds, steering upstream at an angle θ where
sinθ = 1.5/4
θ = 22°