A man in a boat crosses a river 0.1 km wide at his own speed of 18 km / h. The river speed is 5 m / s.

A man in a boat crosses a river 0.1 km wide at his own speed of 18 km / h. The river speed is 5 m / s. Find the time it takes for the boat to cross the river, the distance the boat will carry, the path traveled by the boat.

Task data: Sр (river width) = 0.1 km = 100 m; Vl (own speed of a person on a boat) = 18 km / h = 5 m / s; Vр (river speed) = 5 m / s.

1) Duration of crossing the river: t = Sр / Vл = 100/5 = 20 s.

2) The distance the boat was carried off: Sl = Vr * t = 5 * 20 = 100 m.

3) Boat path: S = √ (Sp ^ 2 + Sl ^ 2) = √ (100 ^ 2 + 100 ^ 2) = 141.4 m.

Answer: The boat will cross the river in 20 seconds; the current will carry the boat 100 m; the boat’s path is 141.4 m.




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