Question

(a) A man crosses a 320 m wide river against the water current in 4 minutes against the current. In still water, he is able to swim with a speed 5 times that of the current. Using vectors, calculate the speed of the current, in m/min

Answer 1

Answer:

20 m/min

Explanation:

Let the speed of the current be x then the speed of the man in still water is :

= 5 × x = 5x

When he swims against the current his speed will be = 5x - x = 4x m/min

Given distance and time the formula for getting speed is :

Speed = Distance / time

In this case :

Distance = 320 m

Time = 4 min

Speed = 320/4 = 80 m/min

80 m/min = 4x

X = 80/4

x = 20 m/min