Consider a swimmer who wants to swim directly across a river as in. If the speed of the current is 0.30 m/s and the swimmer’s speed relative to the water is 0.60 m/s, how long will it take her to cross a river that is 15 m wide?

Answer 1

To find the time it takes for the swimmer to cross the river, we can use the formula:

time = distance / speed

First, we need to find the swimmer's velocity relative to the ground. This can be found using the Pythagorean theorem:

Swimmer's velocity relative to the ground = √((0.60 m/s)^2 + (0.30 m/s)^2)
= √(0.36 + 0.09)
= √0.45
= 0.67 m/s

Now, we can find the time it takes for the swimmer to reach the other side of the river:

time = 15 m / 0.67 m/s
= 22.39 seconds

Therefore, it will take the swimmer approximately 22.39 seconds to cross the 15 m wide river.