Home
Class 11
PHYSICS
Speed of water in river is 5 m/min from ...

Speed of water in river is 5 m/min from west to east. A man can swim with 10 m/min in river water. At what angle should the man swim such that it can reach towards south with shortest path ?

A

At `30^(@)` with flow of water

B

At `60^(@)` with flow of water

C

At `120^(@)` with flow of water

D

towards south

Text Solution

Verified by Experts

The correct Answer is:
C

Suppose velocity of fow of water is `vecv_(R)` and velocity of man is `vecv _(m).`
From figure `sin theeta = (v _(R ))/(v _(m)) = (5)/(10) = (1)/(2) = theta = 30^(@)`
`therefore` direction of velocity of man` = 90^(@)+0 =90^(@) + 30^(@) -120^(@)`
Promotional Banner

Topper's Solved these Questions

  • MOTION IN A STRAIGHT LINE

    KUMAR PRAKASHAN|Exercise QUESTION PAPER|11 Videos

  • MOTION IN A STRAIGHT LINE

    KUMAR PRAKASHAN|Exercise SECTION-E|71 Videos

  • MECHANICAL PROPERTIES OF FLUIDS

    KUMAR PRAKASHAN|Exercise QUESTION PAPER (SECTION -C)|3 Videos

  • OBJECTIVE QUESTIONS AS PER NEW PAPER STYLE

    KUMAR PRAKASHAN|Exercise CHAPTER - 8 (Match Type questions)|5 Videos

Similar Questions

Explore conceptually related problems

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

A man wishes to swim across a river 0.5km. wide if he can swim at the rate of 2 km/h. in still water and the river flows at the rate of 1km/h. The angle (w.r.t. the flow of the river) along which he should swin so as to reach a point exactly oppposite his starting point, should be:-

A river is flowing at 3m//s . A boat can move at 5m//s in still water. Boat starts from point A . Width of river is 120m . Select the incorrect statement :- .

A stone of mass 0.25 kg tied to the end of a string is whirled round in a circle of radius 1.5 m with a speed of 40 rev./min in a horizontal plane. What is the tension in the string ? What is the maximum speed with which the stone can be whirled around if the string can withstand a maximum tension of 200 N ?

A hunter is riding an elephant of height 4 m moving in straight line with uniform speed of 2m//sec . A deer running with a speed V in front at a distance of 4sqrt(5) moving perpendicular to the direction of motion of the elephant. If hunter can throw his spear with a speed of 10m//sec . relative to the elephant, then at what angle theta to it's direction of motion must he throw his spear horizontally for a successful hit. Find also the speed 'V' of the deer.

A swimmer starts to swim from point a to cross a river. He wants to reach point B on the opposite side of the river. The line AB makes an angle 60^(@) with the river flow as hown. The velocity of the swimmer in still water is same as that of the water (i) In what direction should he try to direct his velocity ? Calculate angle between his velocity anf river velocity. (ii) Find the ratio of the time taken to cross the river in this situation to the minimum time in which he can cross this river.

A swimmer starts to swim from point a to cross a river. He wants to reach point B on the opposite side of the river. The line AB makes an angle 60^(@) with the river flow as shown. The velocity of the swimmer in still water is same as that of the water (i) In what direction should he try to direct his velocity ? Calculate angle between his velocity and river velocity. (ii) Find the ratio of the time taken to cross the river in this situation to the minimum time in which he can cross this river.

In the figure there is a long horizontal bridge over a river 75 m high from water surface. A strong man throws a stone in the parallel plane of the bridge. A observer in a car travelling on the bridge finds the stone going pass by the car while ascending and also while descending between two points on the road 30 m away. The car is travelling at a speed of 15 m/s. The stone is thrown from the bank of river just at the same level of water. What is the distance between car and atone at the instant when particle reaches at point B ?

In the figure there is a long horizontal bridge over a river 75 m high from water surface. A strong man throws a stone in the parallel plane of the bridge. A observer in a car travelling on the bridge finds the stone going pass by the car while ascending and also while descending between two points on the road 30 m away. The car is travelling at a speed of 15 m/s. The stone is thrown from the bank of river just at the same level of water. What is the angle the velocity makes with the bridge when it goes past the car while ascending ?

An aeroplane is flying at a constant height of 1960 m with speed 600 kmh^(-1) above the ground towards point directly over a person struggling in flood water. At what angle of sight with the vertical should be pilot release a survival kit if it is to reach the person in water ? (g = 9.8 ms^(-2))

KUMAR PRAKASHAN-MOTION IN A STRAIGHT LINE -SECTION-F
  1. Distance covered by ball thrown upwards with speed 'u' in last 't' sec...

    Text Solution

    |

  2. Ratio of distances covered by object falling freely under gravity in 1...

    Text Solution

    |

  3. Speed of water in river is 5 m/min from west to east. A man can swim w...

    Text Solution

    |

  4. Plane travels 400 m towards north then 300 m towards south and 1200 m ...

    Text Solution

    |

  5. Rate of decrease of velocity of an object moving with 6.25m//s is (dv)...

    Text Solution

    |

  6. An object moving with uniform acceleration covers 40 m in initial 5 se...

    Text Solution

    |

  7. A wheel of 1 m radius completes half rotation on horizontal path. Magn...

    Text Solution

    |

  8. An object falls freely from rest. It covers the same distance in last ...

    Text Solution

    |

  9. A bus starts moving with 1 ms^(-2) acceleration. A man 48 m away from ...

    Text Solution

    |

  10. A stone is thrown upwards with initial velocity 'u' from top of a towe...

    Text Solution

    |

  11. A train starting from a railway station and moving with uniform accele...

    Text Solution

    |

  12. A car moving over a straight path, covers a distance d with constant s...

    Text Solution

    |

  13. A train is moving with constant acceleration. When the ends of a train...

    Text Solution

    |

  14. Rate of decrease in distance between two objects moving with certain s...

    Text Solution

    |

  15. An object is allowed to fall freely from a cliff. When it travels a di...

    Text Solution

    |

  16. The displacement (in metre) of a particle varies with time (in second)...

    Text Solution

    |

  17. Train A 120 m long is moving with 20 m/s. Train B 130 m long is moving...

    Text Solution

    |

  18. A person throws balls upward in regular intervals of time of 2 s. What...

    Text Solution

    |

  19. A bus is moving with a speed of 10m/s on a straight road. A scooteri...

    Text Solution

    |

  20. Two trains moving mutually opposite with some speed on parallel tracks...

    Text Solution

    |