A boat crosses a river with a velocity of $8\, km/h$. If the resulting velocity of boat is $10 \,km/h $ then the velocity of river water is...........$km/h$

An aeroplane is to go along straight line from $A$ to $B$, and back again. The relative speed with respect to wind is $V$. The wind blows perpendicular to line $AB$ with speed $v$. The distance between $A$ and $B$ is $\ell $. The total time for the round trip is

A person running horizontally observes that rain is falling on his head vertically with speed $10\,m/s$. He stops and observes that rain is coming at an angle $30^o$ with vertical. Find the speed of rain w.r.t. ground

A boat is moving with velocity of $3\hat i + 4\hat j$ in river and water is moving with a velocity of $ - 3\hat i - 4\hat j$ with respect to ground. Relative velocity of boat with respect to water is :

Rain is falling vertically with a speed of $30\,ms^{-1}$ . A woman rides a bicycle with a speed of $12\,ms^{-1}$ in east to west direction. She should hold her umbrella

Two cars are moving in the same direction with the same speed $30 \,km/hr$. They are separated by a distance of $5\, km$, the speed of a car moving in the opposite direction if it meets these two cars at an interval of $4$ minutes, will be.......$km/hr$