River Definition and 196 Threads

Homework Statement A swimmer is standing on the west bank of a river 600 m wide. The current in the river is 3.0m/s and the swimmer can swim 5.0 m/s in still water. a) If the swimmer swims due east, what is the time it takes to get across the river? b) What is the minimum time to get across...

Homework Statement A boat is rowed with constant speed u starting from a point A on the bank of a river of width d , which flows with a constant speed nu . The boatman always points the boat at a point O on the other side of the bank opposite to A. Find the equation of the path r = f...

Homework Statement Consider a long straight river flowing north with parallel banks 40m apart. Let us use the function u(x) = 3 sin(\pix/40) to model the rate of water flow x units from the west bank.A boat proceeds at a constant speed of 5m/s from a point A on the west bank while maintaining...

I am given a contour map of the bottom of a river and I must determine how much material must be removed to make the river navigable. Can someone help me by telling me how they'd go about solving this type of problem? My main problem is that I am not so sure what shape(s) to find the volume...

Homework Statement the task is to pump out the river from a cone with R radius and H height. How much will be the work (energy) used to do this? its a problem because I can't use here standard work definition W=\int F(s)\mbox{d}s, and I don't know what to do and how to start. please help:)

Homework Statement Two boys can each paddle their kayaks at the same speed in still water. They paddle across a river which is flowing at a velocity of vR. Boy A aims upstream at such an angle that he actually travels at right angles to vR. Boy B aims at right angles to the bank, but is carried...

Problem: a boat has to cross a river that is 1.5 km wide. There is a current of 5 km/h flowing parallel to the banks of the river. If the boat travels at 12 km/h relative to the water, what is the minimum time it will take the boat to cross the river? The fastest time will be if all of the...

Im taking physics now and I am trying to study for an exam but some of the sample questions in my textbook do not give a an explanation of how to solve them...it's ridiculous. Do they think it will just come to me?! Question:Suppose the river is moving east at 5.00km/h and the boat is...

Homework Statement A: A boat capable of making 11.0 km/h in still water is used to cross a river flowing at speed of 3.0 km/h. At what angle (in o) must the boat be directed (from the perpendicular to the shore) so that its motion will be straight across the river? B: What is the...

Homework Statement A swimmer wants to cross a river, swimming directly from point A to point B, as shown in the figure. The distance d_1 (from A to C) is 179 m, the distance d_2 (from C to B) is 137 m, and the speed v_r of the current in the river is 5.00 km/h. Suppose that the swimmer's...

Homework Statement A swimmer wants to cross a river, swimming directly from point A to point B, as shown in the figure. The distance d_1 (from A to C) is 185 m, the distance d_2 (from C to B) is 141 m, and the speed v_r of the current in the river is 5.00 km/h. Suppose that the swimmer's...

Homework Statement A Boat at Dock A wants to go to Dock B Straight across. Docks are 100m Apart. Vh=4m/s A) If Vo1m=6m/s find the direction he must aim boat (theta) to go straight to dock B B)Find time it takes to get to dock B C)If he aims boat directly north where will he land on the...

Homework Statement A chemical plant produces pesticide that contains a molecule potentially harmful to people if the concentration is too high. The plant flushes out the tanks containing the pesticide once a week, and the discharge flows into the river. The molecule breaks down gradually in...

Pump with no moving parts! Hi! I'm trying to build a "pump" pushing water a few meters up of the river bank, and wondered if I could do it without ANY moving parts (except water :smile:). My plan is to mount a tube (say 50cm in diameter) with one end sealed into a wide river. The open end of...

Homework Statement a boat that can travel at 12.5 m/s on a lake goes 10.6 m/s when going straight up river (with respect to land) if the boat turns and heads (points) 22 degrees upstream from straight across the river. what is the boat's resultant velocity Homework Equations I don't...

Homework Statement Tarzan wishes to swing across a crocodile infested river to consort with Jane, using a vine rope to swing on. In order to reach Jane's side he must swing so that the rope makes a maximum angle of 40 degrees to the vertical. Regarding Tarzan as an 85 kg point mass, what...

Homework Statement A hunter wishes to cross a river that is 1.6 km wide and that flows with a speed of 3.4 km/h. The hunter uses a small powerboat that moves at a maximum speed of 12.4 km/h with respect to the water. What is the minimum time necessary for crossing? Homework Equations...

Homework Statement A swimmer wants to cross a river, from point A to point B, as shown in the figure. The distance d_1 (from A to C) is 200m , the distance d_2 (from C to B) is 150m, and the speed v_r of the current in the river is 5 km/h. Suppose that the swimmer's velocity relative to the...

Introductory Vector Equation Illustrated by a Moving River -- Picture Included Homework Statement A swimmer wants to cross a river, from point A to point B, as shown in the figure. The distance (from A to C) is 100 , the distance (from C to B) is 75 , and the speed of the current in the...

Homework Statement A boat that can travel at 4.0 km/h in still water crosses a river with a current of 1.8 km/h. At what angle must the boat be pointed upstream to travel straight across the river? In other words, in what direction is the velocity of the boat relative to the water? 1...

Homework Statement A 210-m-wide river has a uniform flow speed of 2.4 m/s through a jungle and toward the east. An explorer wishes to leave a small clearing on the south bank and cross the river in a powerboat that moves at a constant speed of 8.4 m/s with respect to the water. There is a...

Homework Statement I have to find the magnitude of the velocity of vector Vcanoe/river of a canoe relative to the river. The canoe has a velocity of 0.520 m/s southeast relative to the earth. The canoe is on the river that is flowing at 0.460 m/s east relative to the earth. The angle...

Homework Statement A hunter wishes to cross a river that is 1.5 km wide and that flows with a speed of 6.6 km/h. The hunter uses a small powerboat that moves at a maximum speed of 14 km/h with respect to the water. What is the time necessary for crossing if the boat goes directly...

Today, I was red-necking it up with some friends in Auburn at the nearby forest. We found an open area on a decent sized creek that was filled with mostly less-than-fist-sized river rock. After dark, we noticed that when a rock was thrown to the ground (on the other rocks), a small spirt of...

Hi. Have you ever heard about tidal bore? Such pretty thing occures on some rivers after the tide, away from river's mouth (on the Amazone river it's called "pororoca"). A few days ago I asked myself: can I define the speed of the bore using high school physics. This is what I've got. Please...

hi! here is a problem for which I cannot really feel the answer though I know the answer here it is A boat can travel at a speed of 3m/s on still water.A boatman wants to croo a river whilst covering the SHORTEST POSSIBLE DISTANCE.in what direction should he row w.r.t the river bank if the...

We all know and love these guys. But they seem so trivial after you solve one. Even if you've solved it ages ago, that formula is still inherent in you somehow and you can bring it up (like bike riding). So when I saw: I automatically went and searched for that file in my brain. Post your...

Homework Statement find the optimal angle so that the time required for the swimmer,runner to cross the river (directly opposite starting position) is minimum. the swimmer swims to one point at the end of the river then he/she will run to the target(opposite from starting position) swim...

Homework Statement A motorboat is going downstream overcame a raft at a Point A; t=60 min later it turned back and after some time passed the raft at a distance l=6km from point A. Find the flow velocity assuming the duty of the engine to be constant. Homework Equations Average...

Plane crashes in NYC river after bird cuts engines http://news.yahoo.com/s/ap/20090115/ap_on_re_us/plane_in_river Well, it had to be more than one bird. Each engine is mechanically independent. If one bird took out both engines, then Airbus needs to rethink the independence of the engines...

Homework Statement Shareen finds that when she drives her motorboat upstream she can travel with a speed of only 8m/s, while she moves with a speed of 12m/s when she heads downstream. What is the current of the river on which Shareen is traveling? The Attempt at a Solution x= current...

Homework Statement A swimmer is to reach at a point 30 degree upstream on the other side of a river flowing with velocity 5 m/s. The velocity of the swimmer w.r.t. water is 5\sqrt{3}. The swimmer should steer at an angle?? The Attempt at a Solution I am unable to guess the scenario...

Homework Statement Two rivers of unequal width (64m and 125m) meet at a right angle, forming an L-shaped channel. What is the longest possible log you can float on it? Homework Equations The Attempt at a Solution I tried for equal widths and built a recursive algorithm for turning...

A fishing boat with a max. velocity of 2m/s is in a river that is flowing at 2m/s west. a. what is the maximum velocity the boat can obtain? is it 4m/s? b. what is the minimum speed? this question i need help answering...

Homework Statement A river flows due North at 3.17 m/s. A boat crosses the river from the West shore to the East shore by maintaining a constant velocity of 8.5 m/s due East relative to the water. If the river is 163 m wide, how far downstream is the boat when it reaches the East shore...

A child is in danger of drowning in the Merimac river. The Merimac river has a current of 3.1 km/hr to the east. The child is 0.6 km from the shore and 2.5 km upstream from the dock. A rescue boat with speed 24.8 km/hr (with respect to the water) sets off from the dock at the optimum angle to...

A river is 0.76 km wide. The banks are straight and parallel. The current is 4.0 km/h and is parallel to the banks. A boat has a maximum speed of 3.0 km/h in still water. The pilot of the boat wishes to go on a straight line from A to B, where AB is perpendicular to the banks. What should the...

Homework Statement (1) A River flows due east at 1.20 m/s. A boat crosses the river from the south shore to the north shore by maintaining a constant velocity of 9.0 m/s due north relative to the water. I got the velocity of the boat relative to shore at 9.08 m/s at 82.406 degrees north of...

A farmer has two miles of fence, and wants to enclose the max possible area for his cows. He will use fence on only three sides because the fourth side is a river that flows through his land. The path of the river is the parabola y=4-x^2. One of the ends of the fence is on the vertex of the...

Homework Statement A boat takes 2.0 hr to travel 31 km down a river, then 6.0 hr to return. How fast is the river flowing? Homework Equations r=d/t The Attempt at a Solution first started out by finding the rate the boat traveled in each trip. 31/2=15.5 km/hr 31/6=5.2...

Submersed water pump for river flows. Two cylinders, one with 1 meter diameter and the other 0.2 m/diameter. Pistons are in the same shaft. Area ratio is of 25 X. The bigger cylinder have a shroud of a diameter of 1.5 meter in both ends and is open on both sides. When we submerse it in the...

Swollen Cedar River Floods Iowa Cities http://www.npr.org/templates/story/story.php?storyId=91488984 The middle (midwest) part of the country has been getting hammered by storms recently. Apparently tornadic activity may set a record this year, and flooding in some cases is setting...

A swimmer crosses a flowing river of width d to and fro in time t1. The time taken to cover the same distance up and down the stream is t2. If t3 is the time the swimmer would take to swim a distance 2d in still water, then prove that t1 square = t2t3.

[SOLVED] work and power Homework Statement the Grand Coulee Dam on the Columbia River is 1270 m long and 170 m high. The electrical power output from the generators at its base is approximately 2000 MW, How many cubic meters of water much flow from the top of the dam per second to produce...

I have a test on Friday on this...now my textbook, 2 physics teachers and other people say I'm wrong but i know i still think I'm right. what is the right way to answer this i explained option 2 is correct. please give explanation of why, or examples i can use to prove it. Thank you! A...

A canoeist who can paddle 5km/h in still water wishes to cross a 400 m wide river, with 2km/h current. If he steers the canoe perpendicular to the current and wants to get straight across the river how long will it take him to cross the river. Which way is right? and why? hypotenuse = 5 km/h...

Homework Statement In his rowboat, Pierre heads directly across a river at a speed of 10 km/h. The river is 120m wide and is flowing at 6 km/h. Suppose Pierre wants to row directly across the river. At what angle relative to the shore should he head? I would really appreciate help with...

[SOLVED] River channel problem using Bernoulli and Continuity Homework Statement A river (100 m wide) flows through its rectangular channel at a depth of 2.560 m at a velocity of 2.050 m/s. What is the velocity of the discharge if the channel is narrowed to 90 m? Homework Equations...

A 310-m-wide river has a uniform flow speed of 1.6 m/s through a jungle and toward the east. An explorer wishes to leave a small clearing on the south bank and cross the river in a powerboat that moves at a constant speed of 4.4 m/s with respect to the water. There is a clearing on the north...

A boat takes 2.6 hours to travel 28.43 km down a river, then 5.5 hours to return. How fast is the river flowing? So we want to find the velocity the river has. I'm not sure I even started this right. First I converted 2.6 hours to seconds = 9360 s Then 5.5 hours to seconds = 19800 s...