Boat Definition and 366 Threads

  1. P

    Resultant Velocity of sailing boat

    Homework Statement A boat is sailing on a bearing of 120° and has a speed of 4ms^-1 relative to water. A current has a speed of 2ms^-1 and flows south west. Find the resultant speed of the boat 2. The attempt at a solution I've been stuck on this question for an hour now and can't...
  2. S

    Vectors - Boat & Stream problem

    Homework Statement A boatman wants to cross a canal that is 3 km wide and wants to land at a point 2 km upstream from his starting point. The current in the canal flows at 3.5 km/h and the speed of his boat is 13 km/h. (a) In what direction should he steer? (b) How long will the trip take...
  3. J

    Is water level the same after an anchor is thrown from a boat?

    Homework Statement (5) A person sitting in a boat floating on a small pond throws a heavy anchor overboard. Does the level of the pond rise, fall, or stay the same? Explain. Homework Equations FB=mass of fluid displaced times g Fnety=Fb-mg The Attempt at a Solution...
  4. N

    Does Sequential Rowing Increase Boat Speed?

    After watching a few rowing competitions of London Olympics 2012, a question came to my mind. In the competitions rowers (Not sure if this is the word used for athletes) synchronize their rowing strokes. All 8 athletes' oars touch and leave water at the same time. This causes the boat to...
  5. S

    What Is the Purpose of a Water Cooling System Vent on a Boat?

    Hi, Can somone explain to me what this contraption is(Upon querying the boat-man,he replied it had something to do with water cooling the engines). (//postimage.org/image/4g03vm1bn/),but this "thing" was at the boat aft.Is this some kind of a siphon exit? Isn't the water input supposed...
  6. M

    What data do I need to consider when designing a magnetohydrodynamic boat?

    I am trying to design a boat using magneto hydrodynamic engine MHD what sort of data should i be taking in account? the voltage, current, electric field strength, the velocity of the boat but what else should i look at ?
  7. T

    A Man In a Speed Boat Top Speed 15m/s

    1. A man in a speed boat, top speed, 15m/s, is crossing a river, 1000m wide, flowing East at 2m/s. The man steers the boat so as to reach a point 150m upstream on the opposite bank. What angle, WthetaN should he steer at? How long does the crossing take? 2. (Velocityx-2)(T)=-150...
  8. N

    Maximising water flow into an intake on a race boat

    I've looked at lot of information on the net and have picked up a few things. My query is how to work out the optimum radius and measurements for the lead into an intake on a racing jet boat? We cruedly term it the 'spoon effect' where the water runs along the bottom of the boat and up into...
  9. S

    Center of Mass boat distance from shore what am I doing wrong?

    Problem: A symmetrical rowboat, mass M = 116 kg, length L = 6.89 m, points toward the shore. A man, mass m = 90 kg, stands in the back of the boat, distance d = 35.7 m from the shore. If the man now walks to the front of the boat, how far will he be from the shore? Here is what I did...
  10. M

    Multivariable calc, boat moving on river functions problem

    Homework Statement there is a straight river 40m wide. the water speed on the river can be expressed as the function f(x)=3sin(∏x/40) If a boat is to cross the river from point a to point b at a constant velocity of 5 m/s determine the angle the boater should head. Homework Equations...
  11. Z

    Velocity of a Boat and Float vs. Water

    A boat is heading upstream when a float is dropped overboard and carried downstream. After 1 hour, when the boat is has traveled 2.0 km farther upstream, it turns around and catches up with the float 5.0 km downstream from the turnaround point. If the boat travels with constant velocity: How...
  12. Rapier

    Buoyancy (A Boat in Water vs Alcohol)

    Homework Statement You take a toy boat, float it in a tub of water and one half of the boat is below the surface. According to Archimedes’ Principle, how much of the boat would be below the surface if you tried to float it in a tub of alcohol? →Less than half. →Half. →More than half, but...
  13. F

    Center of Mass: Boat and regular pentagon

    Six problems due Monday, and I have no idea what I'm doing on either of these. Problem 1: Homework Statement A group of people has a total mass of 1500kg and are standing on one end of a 20,000kg boat. They walk 6.5m to the other end of the boat. How much does the boat move? The water...
  14. C

    Does Nozzle Orientation Affect Speed in Compressed Air Powered Boats?

    I saw on myth busters where they took compressed air tanks an attached them to a boat and then opened the valve and then the boat started to move. They did 2 trials, one where the exhaust nozzle was pointed above the water and one where it was pointed in the water. Then one that was pointed...
  15. B

    How to Calculate the Angle for a Boat Crossing a River with a Current?

    Homework Statement A boat that can travel at 4.0km/h in still water crosses a river with a current of 2.0 km/h. At what angle must the boat be pointed upstream (that is, relative to its actual path) to go straight across the river? Homework Equations No equations were given but it...
  16. D

    Buoyant Force and Displacement Volume of a Boat in Lake Superior

    Homework Statement A boat full of people lazily drifts along in Lake Superior. The boat has a mass, including people of 15,450kg. A. What is the buoyant force? B. What is the volume of the displaced liquid in cubic meters? The Attempt at a Solution A. Fb=mg Fb=? m=15,450kg g=...
  17. 1

    I am so confused, water displaced by a boat

    Homework Statement A boat floating in fresh water displaces water weighing 34.7 kN. (a) What is the weight of the water that this boat displaces when floating in salt water of density 1.10 x 10^3 kg/m3? Homework Equations The Attempt at a Solution I am utterly confused. They...
  18. G

    Find the angle the boat has to head

    Homework Statement A boat, which can travel at 8.2 m/s in still water, heads directly across a river which has a current of 4.5 m/s and is 477 meters wide. What should the heading of the boat be in order for it to land at a point on the opposite shore exactly 100 m upstream from the starting...
  19. J

    Find the power of a boat that accelerated

    A 3.5x107 kg ship is traveling at 7 m/s. The ship is accelerated forward with a F of 4.5 x 105 N over a distance of 2 km. What is the final speed? Vf = 10 m/s How long does it take the ship to traverse the 2 km? T = 233.33 seconds What is the average power which the engines had to...
  20. S

    Velocity of boat in river with varying current

    Homework Statement See attached. Homework Equations The Attempt at a Solution I originally began by assuming the rate was constant, obtaining the equations V_x^2 + V_y^2 = 1 \tan{\sigma} = \frac{V_y}{V_x} with the assumptions V_x(\sigma) = f(\sigma) V_y(\sigma) =...
  21. 2

    What Direction Should a Man Row a Boat to Cross a River in the Shortest Time?

    Homework Statement A man can row a boat at 4 m/s in still water. The current in a river is 2 m/s. The river is 40 m wide. If he wants to cross the river in the smallest possible time at what direction should he aim the boat? Given: V[B,E] = 4m/s V[W,E] = 2 m/s Down is negative. Homework...
  22. D

    Center of mass question (man on a boat)

    Homework Statement A man with mass m1 = 60 kg stands at the left end of a uniform boat with mass m2 = 169 kg and a length L = 2.7 m. Positive x is pointing to the right. Assume there is no friction or drag between the boat and water. After the man walks to the right edge of the boat, what is...
  23. L

    Boat crossing river problem using reference frames

    Homework Statement A 110-m-wide river flows due east at a uniform speed of 3.3 m/s. A boat with a speed of 8.6 m/s relative to the water leaves the south bank pointed in a direction 37 degrees west of north. What is the (a) magnitude and (b) direction of the boat's velocity relative to the...
  24. A

    Man on a Boat: Finding the Center of Mass

    Homework Statement A man with mass m1 = 60 kg stands at the left end of a uniform boat with mass m2 = 165 kg and a length L = 3.6 m. Let the origin of our coordinate system be the man’s original location as shown in the drawing. Assume there is no friction or drag between the boat and water...
  25. O

    What is the maximum possible volume of a parabolic sailboat hull?

    Homework Statement The design of boats is based on Archimedes' Principle, which states that the buoyant force on an object in water is equal to the weight of the water displaced. Suppose you want to build a sailboat whose hull is parabolic with cross section y=ax2, where a is a constant. Your...
  26. Femme_physics

    Boat Tugging a Whale: Solving 2 Unknowns

    Am getting stuck with 2 unknownsHomework Statement http://img40.imageshack.us/img40/5883/whaltboat.jpg The 5.5-Mg humpback whale is stuck on the shore due to changes in the tide. In an effort to rescue the whale, a 12-Mg tugboat is used to pull it free using an inextensible rope tied to its...
  27. K

    Wind turbine on a boat efficient?

    I recently read this http://www.earthtechling.com/2011/06/wind-turbines-board-europe-ferries/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Earthtechling+%28EarthTechling%29&utm_content=Google+Reader" and it's really bugging me. They claim that by putting wind turbines on the...
  28. P

    Waves and A Fisherman on a boat

    a water wave is traveling in a straight line on a lake is described by the equation y(x,t)=.0375mcos(.0045 m^-1 (x) + 5.4 s^-1 (t)) How much time does it take for one complete wave pattern to go past a fisherman in a boat at anchor, and what is the horizontal distance does the wave crest...
  29. P

    How to Find Force F on a Boat with Given Forces and Motion?

    A 325-kg boat is sailing 15.0° north of east at a speed of 2.00 m/s. Thirty seconds later, it is sailing 35.0° north of east at a speed of 4.00 m/s. During this time, three forces act on the boat: a 31.0N force directed 15.0° north of east, a 23.0N force directed 15.0° south of west and F Find...
  30. I

    Physics of tubing behind a boat.

    Physics of "tubing" behind a boat. I have noticed that when an inflatable tube (usually with a passenger on top) is being pulled fast behind a speedboat, and the boat turns (in a sustained sharp turn), it seems as if the tube and rider achieve speeds that are faster than that of the boat...
  31. U

    Magnet attached to boat, would it work?

    Magnet attached to boat, would it work!? OK, if there was a boat with a magnet held in front of it by some sort of arch/crane attached to the boat would the boat be pulled towards the magnet, thus moving the boat forward, or would it just stay still. ______ o [________]...
  32. F

    How Can You Build a Self-Propelling Boat That Also Launches a Projectile?

    Homework Statement 1. The Project I must build a boat that is able to propel itself via elastic or gravitational energy 1.0 metres. After it has moved 1.0m, it must automatically shoot a projectile 2.0m perpendicular to the movement. 2. Rules The boat cannot touch the bottom of the 10...
  33. P

    What is the resultant speed and resultant angle of the boat?

    Homework Statement A rowboat starts across river. If the average speed of the boat is 5.39 m/s and the river is flowing at a speed of 2.91 m/s, what is the resultant speed and resultant angle of the boat? i know this is super basic but i havn't done this type of problem since the...
  34. R

    Calculating Wave Speed & Distance from Boat

    Homework Statement the speed of waves on a lake depends on frequency. For waves of frequency 1.0 Hz the wave speed is 1.56 m/s; for 2.0 Hz waves the speed is .78 m/s. the 2.0 Hz waves reach you 120 seconds after the 1.0Hz waves generated by the same boat. How far away is the boat...
  35. C

    A boat and trailer are being pulled along a bumpy road at a velocity

    A boat and trailer are being pulled along a bumpy road at a velocity v. The contour of the road can be approximated by a sine wave with a wavelength l of 10ft and an amplitude y of .5 in. the deflection of the springs in the trailer due to the boats weight is 1.5in. the damping of the system is...
  36. S

    Total force resisting the forward motion of a boat at a speed

    Problem: A boat powered by an engine rated at 100 kW can reach a top speed of 70.0 km/h. What is the total force resisting the forward motion of the boat at this speed? I don't know which equations to use :(
  37. Y

    Physics Project: The Famous Foil Boat

    Homework Statement I know that (for a given mass) the volume of an object affects its density. The greater the volume, the lower the density; the lesser the volume, the higher the density. Thus, the lower the density, the more pennies the boat can hold before sinking. My question is, how can...
  38. C

    Inflatable Boat Capacity 420L - Load Capacity Calculation

    Homework Statement Inflatable boat with a capacity of 420 liters, floating in empty, so that 91% of the volume is above the water surface. The density of water is 1020 kg/m3 Homework Equations How big load in kilograms can be loaded, top of the sink to be just the water surface level...
  39. E

    Kinematics - Boat over a constant River.

    Homework Statement A 400m wide river flows from west to east at 30 m/min. Your boat moves at 100m.min relative to the water no matter which direction you point. To cross the river, you start from a dock at point A on the south bank. There is a boat landing directly opposite at point B on...
  40. P

    What is the Time Limit for Boarding the Bobbing Boat?

    Homework Statement Don’t Miss the Boat. While on a visit to Minnesota (“Land of 10,000 Lakes”), you sign up to take an excursion around one of the larger lakes. When you go to the dock where the 1500- kg boat is tied, you find that the boat is bobbing up and down in the waves...
  41. T

    How long does it take to slow this boat down?

    Homework Statement A 1000 kg boat is traveling at 90 km/h (25 m/s) when the its engine is shut off. The magnitude of the frictional force fk is proportional to the speed v of the boat: fk = 70v; where v is in meters per second and fk is in Newtons. Find the time required for the boat to slow...
  42. A

    Boat travelling in river without current

    Homework Statement This is a question from Gelfand's Algebra: A boat traveling upstream from A to B can cover the distance in a hours. The boat can travel downstream from B to A in b hours. How long would it take to travel from A to B if there was no current? The Attempt at a...
  43. P

    Does Drinking Water From a Boat Affect Water Level?

    a person is sitting in boat which is floating in water he drinks water by lowering himself from the boat will the water level rise and why i am not getting the question Homework Equations The Attempt at a Solution
  44. Z

    Calculating speed of boat by sail alone

    Hello all, I know this is probably very simple stuff, but I'm a mature student, and a bit rusty. Essentially, I need to calculate the following: a sailboat of mass 52 tonnes, dimensions 50m x 6m x 2m, and square shaped sail of 150 m^2 is sailing by wind alone, which has a speed of 15 m...
  45. V

    How Does the Dog's Movement Affect Its Distance from the Shore?

    Homework Statement A dog with mass 11 kg stands still in a boat with mass 45 kg. the dog is 20 meters from the shore. It then walks 8 meters in the boat towards the shore. how far is the dog from the hore aftter this? Homework Equations center of mass equation The Attempt at a...
  46. D

    Calculating Drag Force on Boat: Speed as Function of Time

    F = -kv2 A fishing boat of mass m moves through the water in the +x direction. At time = 0 and x=0 it shuts its engines off and begins to drift. It experiences drag according to the above equation, calculate the boat's speed as a function of time. I've tried taking F = ma so a = -kv2/m...
  47. JJBladester

    Man and Woman on Boat - Velocity of Boat after Dive

    Homework Statement A 180-lb man and a 120-lb woman stand side by side at the same end of a 300-lb boat, ready to dive, each with a 16-ft/s velocity relative to the boat. Determine the velocity of the boat after they have both dived, if (a) the woman dives first, (b) the man dives first...
  48. C

    Hydrophobic properties of boat hulls

    By increasing the hydrophobicity of canoe hull material, will drag be reduced? Have hydrophobic materials been used on boats? My thoughts: Yes, there is less surface contact with the water. Thus less viscous (friction) forces.
  49. E

    What Angle Should a Rower Use to Cross a River with a Current?

    A woman who can row a boat at 6.5 km/h in still water faces a long, straight river with a width of 6.1 km and a current of 3.4 km/h. Let point directly across the river and point directly downstream. (a) If she rows in a straight line to a point directly opposite her starting position, at...
  50. W

    How to Calculate Time and Displacement for a Ferry Boat Crossing a River?

    Homework Statement A ferry boat is crossing a river that is 8.5 x 10^2m wide. The average velocity of the waer relative to the shore is 3.8m/s (e) and the average velocity of the boat relative to the water is 4.9m/s (s). Homework Equations The Attempt at a Solution So i got the...
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