A child in danger of drowning in a river is being carried downstream by a current that has a speed of 2.70 km/h. The child is 0.600 km from shore and 0.800 km upstream of a boat landing when a rescue boat sets out.
(a) If the boat proceeds at its maximum speed of 20.0 km/h relative to the water, what heading relative to the current should the pilot take?
° relative to the direction of the current
(b) What angle does the boat velocity make with the current?
° relative to the direction of the current
(c) How long does it take the boat to reach the child?
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2007-09-18 11:54:16 · 1 answers · asked by justin l 1 in Science & Mathematics ➔ Physics
The moment the boat sets out it is in the same frame of reference as the child, in a moving river. Since both the child and the boat are affected by the same current, it is as if the boat and the child are on a still pond. This is a 3-4-5 right triangle, where the hypotenuse is 1 km. The boat will proceed to the child at 20 km/hr w/r/t the water and the child. The angle is ATAN(3/4). The transit time is 60/20 minutes, or three minutes.
j
2007-09-19 03:59:26 · answer #1 · answered by odu83 7 · 0⤊ 0⤋