Question

problem 2: a swimmer crosses a river with a velocity of v = (2.1,0.8) m/s. the width of the river is along the x axis. if the width of the river is 32 m, find the time it took for the swimmer to cross the river.

Explanation:

Step1: Identify relevant velocity component

The width of the river is along the x - axis. We need the x - component of the velocity vector $\vec{v}=(2.1,0.8)\ m/s$. The x - component $v_x = 2.1\ m/s$.

Step2: Use the formula for time

The formula for time $t$ when moving with a constant velocity $v$ over a distance $d$ is $t=\frac{d}{v}$. Here, $d = 32\ m$ (width of the river) and $v = v_x=2.1\ m/s$. So $t=\frac{32}{2.1}\ s$.

Answer:

$\frac{32}{2.1}\approx15.24\ s$