Home
Class 12
PHYSICS
Two ports, A and B, on a north-south lin...


Two ports, A and B, on a north-south line ar separated by a river of width D. The river flows east with speed u. A boat crosses the river starting from port A. The speed of the boat relative to the river is v. Assume `v=2u`
Q. Suppose the boat wants to cross the river from A to the other side in the shortest possible time. Then what should be the direction of the velocity of boat relative to river?

A

`30^@` west of north

B

`30^@` east of north

C

`60^@` west of north

D

along north

Text Solution

Verified by Experts

The correct Answer is:
B
To cross the river the fastest, we need to maximize the y-component of the total velocity is `V_(B)costheta` So `theta=0`. The boat should head straight to the north.
Take positive x-axis along east and positive y-axis along north.
Promotional Banner

Topper's Solved these Questions

  • CENGAGE PHYSICS DPP

    CENGAGE PHYSICS ENGLISH|Exercise Multiple correct Answer Type|54 Videos

  • CENGAGE PHYSICS DPP

    CENGAGE PHYSICS ENGLISH|Exercise Single Correct Answer type|491 Videos

  • CENGAGE PHYSICS DPP

    CENGAGE PHYSICS ENGLISH|Exercise single correct type|14 Videos

  • CAPACITOR AND CAPACITANCE

    CENGAGE PHYSICS ENGLISH|Exercise Integer|5 Videos

  • COULOMB LAW AND ELECTRIC FIELD

    CENGAGE PHYSICS ENGLISH|Exercise Single Answer Correct Type|22 Videos

Similar Questions

Explore conceptually related problems

Two ports, A and B, on a north-south line ar separated by a river of width D. The river flows east with speed u. A boat crosses the river starting from port A. The speed of the boat relative to the river is v. Assume v=2u Q. The boat crosses the river from A to the other side in shortest possible time, then how far is the boat from the port B after crossing the river

Two ports, A and B, on a north-south line ar separated by a river of width D. The river flows east with speed u. A boat crosses the river starting from port A. The speed of the boat relative to the river is v. Assume v=2u Q. What is the direction of the velocity of boat relative to river theta , sothat it crosses directly on a line from A to B?

A boat which has a speed of 6km/h in still water crosses a river of width 1 km along the shortest possible path in 20 min. the velocity of the river water in km/h is

A river is flowing from west to east at a speed of 5m//s . A man on the south bank of the river capable of swimming at 10m//s in a still water wants to swim, across the river in a shortest time. He should swim in a direction

A river is flowing from west to east at a speed of 5 metres per minute.A man on the south bank of the river, capable of swimming at 10 metres per minute in still water, wants to swim across the river in the shortest time. He should swim in a direction.

A river is flowing from west to east at a speed of 5 metres per minute.A man on the south bank of the river, capable of swimming at 10 metres per minute in still water, wants to swim across the river in the shortest time. He should swim in a direction.

A man who can swim at a velocity v relative to water wants to cross a river of width b, flowing with a speed u.

A man who can swim at a velocity v relative to water wants to cross a river of width b, flowing with a speed u.

A boat crosses river of width 60sqrt(7)m inshortest possible path.Speed of river is 8m/s and speed of the boat in , still water is 6m/s .Find the time taken by boat(in seconds) to cross the river.

A swimmer can swim in still water with speed v and the river is flowing with speed v//2 . What is the ratio of the time taken to swimming across the river in shortest time to that of swimming across the river over the shortest distance ?

CENGAGE PHYSICS ENGLISH-CENGAGE PHYSICS DPP-Comprehension Type
  1. A man is standing on top of a building 100 m high. He throws two ball ...

    Text Solution

    |

  2. A man is standing on top of a building 100 m high. He throws two ball ...

    Text Solution

    |

  3. A boy in the elevator shoots a bullet in a vertical upward direction f...

    Text Solution

    |

  4. A boy in the elevator shoots a bullet in a vertical upward direction f...

    Text Solution

    |

  5. A boy in the elevator shoots a bullet in a vertical upward direction f...

    Text Solution

    |

  6. A boy in the elevator shoots a bullet in a vertical upward direction f...

    Text Solution

    |

  7. Points A and C are on the horizontal ground and A and B are in same ve...

    Text Solution

    |

  8. Points A and C are on the horizontal ground and A and B are in same ve...

    Text Solution

    |

  9. Points A and C are on the horizontal ground and A and B are in same ve...

    Text Solution

    |

  10. Two ports, A and B, on a north-south line ar separated by a river of w...

    Text Solution

    |

  11. Two ports, A and B, on a north-south line ar separated by a river of w...

    Text Solution

    |

  12. Two ports, A and B, on a north-south line ar separated by a river of w...

    Text Solution

    |

  13. A block of mass m is placed on a rough inclined plane. The corfficient...

    Text Solution

    |

  14. A block of mass m is placed on a rough inclined plane. The corfficient...

    Text Solution

    |

  15. A block of mass m is placed on a rough inclined plane. The corfficient...

    Text Solution

    |

  16. A block B is placed over a cart which in turn lies over a smooth horiz...

    Text Solution

    |

  17. A block B is placed over a cart which in turn lies over a smooth horiz...

    Text Solution

    |

  18. A block B is placed over a cart which in turn lies over a smooth horiz...

    Text Solution

    |

  19. A small block of mass m is pushed on a smooth track from position A wi...

    Text Solution

    |

  20. A small block of mass m is pushed on a smooth track from position A wi...

    Text Solution

    |