A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

Abhisar

  • one year ago

A man wishes to swim across a river 0.5 m wide. If he can swim at the rate of 2 Km/ h in still water and the river flows at the rate of 1 km/hr. The angle (wrt flow of water) along which he should swim so as to reach a point exactly opposite his starting point, should be?

  • This Question is Closed
  1. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Nuu..

  2. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1437500992112:dw|

  3. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1437501550342:dw|

  4. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Time taken to cross the river = 0.5/2 = 1/4 Now in the same time the boat will travel a horizontal distance of AB. So AB = 1/4 * speed of river water = 0.25 Km Now, AB/BO = tan <AOB

  5. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    So the answer should be tan -1 <AOB + 90... correct?

  6. paki
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    From where you got these angles...?

  7. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Which angle?

  8. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1437501819590:dw|

  9. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You were typing from the morning and you wrote from where you got those angles? @paki :P

  10. paki
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    lml... lag for me... sorry... :/

  11. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Are you guys able to spot the mistake?

  12. paki
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1437501941480:dw|

  13. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    From where you have taken boat in between this question? You got it for free?

  14. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @paki the question want us to find the angle with respect to flow of water along which the boat should go. @waterineyes the boat is goingg along the line OA

  15. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Wait, the man is swimming or he is in the boat??

  16. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    lol, whatever :D I forgot..he is swimming

  17. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    See, his speed of swimming is 2 km/h, and that of river is 1 km/h, he has to swim against the flow, so you need to find relative speed no?

  18. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Or relative velocity.. I mean, why you divide that by 2, where is the river speed then?

  19. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Ummm..not really. Read ex 1 of boat problems here http://www.physicsclassroom.com/class/vectors/Lesson-1/Relative-Velocity-and-Riverboat-Problems

  20. paki
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Pythagorean theorem

  21. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay, I understood, that he will swim regardless or water current, and with his own speed, he will reach to point A..

  22. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yes

  23. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    *reach point A..

  24. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You have to find resultant velocity buddy..

  25. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Give me some time..

  26. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ok..

  27. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay...

  28. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    See, the man has to swim straight, but river flow will make him flow as hypotenuse direction..

  29. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    The man wants to reach the exact opposite point so he should swim along the hypotenuse on purpose so that river flow will make him reach on the opp side along a straight line.

  30. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1437502730218:dw|

  31. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    YEs, man should swim along OB...right?

  32. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay then I am misinterpreting the question, wait more then.. :P

  33. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    If we move along OB, then river flow must be opposite to reach A. Scratch that diagram.. :)

  34. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1437502906907:dw|

  35. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay, let me now again try..

  36. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1437503017553:dw|

  37. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1437502994510:dw|

  38. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You can use Pythagoras theorem to find the unknown side... \[R = \sqrt{2^2 - 1^2 } = \sqrt{3} \quad km/hr\]

  39. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1437503162276:dw|

  40. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    one min

  41. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    YaY!!!

  42. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Done...... dhika chika dhinka chika

  43. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Aise hi hoga na, main to bas tukke jyada aur dimaag kam chala raha tha. :P

  44. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Pata nahi answer to aa gaya :D

  45. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I got its nerve.. See, you have to take river flow and man or boat flow as vectors, draw them on paper to know their directions, on its basis you will get whether to subtract them in squares or to add them. :)

  46. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Once you find the unknown, finding angle is just a-jiffy work..

  47. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Ahaann...I see but there must be another way, something like i was doing earlier. I will mess with it tomorrow. But thank you, cz of uh i can seep in peace now :)

  48. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    *sleep

  49. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Don't forget to wake up.. :P

  50. Abhisar
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I wish I could :D

  51. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.