# Physics help please! A river flows due south with a speed of 2.0 m/s . A man steers a motorboat across the r?

"1) A river flows due south with a speed of 2.0 m/s . A man steers a motorboat across the river. The river is 800 m wide

a) In which direction should the motorboat head in order to reach a point on the opposite bank directly east from the starting point? (The boat's speed relative to the water is 4.2m/s .)

b) What is the velocity of the boat relative to the earth?

c) How much time is required to cross the river?"

18-02-2013

06-03-2013
"1) a) I visualized the situation by drawing the river as a vertical strip. Relative to the horizontal, let the angle (direction) of the motorboat be x. Then, the vertical component would be 4.2 sin x. For the motorboat to be exactly east, then the vertical components must cancel, leaving only the east horizontal component of the motorboat. Thus, 4.2 sin x = 2.0 x = 28.4 = about 28 degrees (ANSWER) b) The velocity of the boat relative to the earth is the horizontal component since the vertical components cancel. 4.2 cos x = 4.2 cos 28.4 = 3.69 = about 3.7 m/s (ANSWER) c) t = x/v for constant velocity = 800/3.7 = 216 = about 220 s (ANSWER)"
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15-05-2013
Estuaries in addition to waterways usually are portion of the hydrological world. H2o inside a normal water is certainly caused by gathered by using hastiness by using a river basin via floor overspill besides other choices as well as groundwater recharge, comes, as well as ease stashed nutrient mineral water end-to-end standard this rubble as well as snowpacks (electronic.gr., by means of the rocks). Potamology would be the study affecting estuaries and rivers even though limnology is the inquiry regarding countrywide seas generally.
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