Velocity of the river water is 3m/s and velocity of a boat in still waters in 5m/s. If the distance between the banks of a river is 50 m, then calculate the time taken for (ii) longest distance to cover.

Explanation

Longest distance covered by the boat,
`v_(b)=sqrt(v_(b)^(2)+v_(w)^(2))`
Hence `t=(d)/(v'_(b))=(50)/(sqrt(5^(2)+3^(2)))`
`t=8.57s`.