Home
Class 11
PHYSICS
An open merry go round rotates at an ang...

An open merry go round rotates at an angular velocity `omega`.A person stands in it at a distance `r` from the rotational axis.It is raining and the rain drops falls vertically at a velocity `v_(0)`.How should the person hold an umbrella to prorect himself from the rain in the best way.Angle made by umbrealla with the vertical is

A

`cot alpha=v_(0)/(romega)`

B

`tan alpha=v_(0)/(romega)`

C

`cot alpha=(romega)/v_(0)`

D

`tan alpha=v_(0)/(romega)`

Text Solution

Verified by Experts

The correct Answer is:
A
Let th velocity of the drops above the person `rel.` to the merry go round be at angle `alpha` to the vertical. This angle can be determined from the velocity triangle `v_(0)=v_(rel)+v_(m.g.r)`,
`v_(rel)=v_(0)-v_(m.g.r)=(romega),cot alpha=v_(0)/(romega)`.
Promotional Banner

Topper's Solved these Questions

  • MOTION IN A PLANE

    NARAYNA|Exercise Level-Vi multiple answer|16 Videos

  • MOTION IN A PLANE

    NARAYNA|Exercise Level-VI Passage answer|18 Videos

  • MOTION IN A PLANE

    NARAYNA|Exercise Integer|6 Videos

  • MECHANICAL PROPERTIES OF SOLIDS

    NARAYNA|Exercise LEVEL-II (H.W)|24 Videos

  • MOTION IN A STRAIGHT LINE

    NARAYNA|Exercise Level 2 H.W|29 Videos

Similar Questions

Explore conceptually related problems

An open merry-go-round rotates at an angular velocity omega . A person stands in it at a distance r from the rotational axis. It is raining, and the raindrops fall vertically at a velocity v_(0) . How should the person hold an umbrella to protect himself from the rain in teh best way ?

A boy is running on a horizontal road with a velocity of 5 m/s. At what angle should he hold his umbrella in order to protect him self from the rain if the rain is falling vertically with a velocity of 10 m/s?

A man walking on a road with a velocity of 5 km per hour encounters rain falling vertically with a velocity of 25 km per hour. At what angle should he holds his umbrella in order to protect himself form the rain?

If rain falls vertically with a velocity V_r and wind blows with a velocity V_w from east to west, then a person standing on the roadside should hold the umbrella in the direction

A man is going due east with a velocity of 5ms^(-1) .It is vertically rainging downwards with a velocity of 4ms^(-1) .At what angle should he hold the umbrella to the vertical so as to protect him self from the rain?

A man is going due east with a velocity of 3 kmh^(-1) . Rain falls vertically downwards at a speed of 10 km h^(-1) . Calculate the angle at which he should hold his umbrella so as to protect himself from rain.

Rain is falling vertically. A man running on the road keeps his umbrella tilted but a man standing on the street keeps his umbrella vertical to protect himself from the rain. But both of them keep their umbrella vertical to avoid the vertical sun-rays. Explain.

When it is raining vertically down, to a man walking on road the velocity of rain appears to be 1.5 times his velocity.To protect himself from rain he should hold the umbrealla at an angle theta to vertical. The tan theta=

A stationary person observes that rain is falling vertically down at 30 km//hr . A cyclist is moving up on an inclined plane making an angle 30^(@) with horizontal at 10 km//hr . In which direction should the cyclist hold his umbrella to prevent himself from the rain ?

By the term velocity of rain, we mean velocity with which raindrops fall relative to the ground. In absence of wind, raindrops fall vertically and in presence of wind raindrops fall obliqucly. Moreover raindrops acquire a constant terminal velocity due air resistance very quickly as they fall toward the carth. A moving man relative to himself observes an altered velocity of raindrops. Which is known as velocity of rain relative to the man. It is given by the following equation. vec(v)_(rm)=vec(v)_(r)-vec(v)_(m) A standstill man relative to himself observes rain falling with velocity, which is equal to velocity of the raindrops relative to the ground. To protect himself a man should his umbrella against velocity of raindrops relative to himself as shown in the following figure. Rain is falling vertically with velocity 80 cm/s. (a) How should you hold your umbrella ? (b) You start walking towards the east with velocity 60 cm/s. How should you hold umbrella ? (c) You are walking towards the west with velocity 60 cm/s. How should you hold your umbrella ? (d) You are walking towards the north with velocity 60 cm/s. How should you hold your umbrella? (e) You are walking towards the south with velocity 80 cm/s. How should you hold your umbrella ?

Knowledge Check

  • If rain falls vertically with a velocity V_r and wind blows with a velocity V_w from east to west, then a person standing on the roadside should hold the umbrella in the direction

    A
    `tan theta = V_w/V_r`
    B
    `tan theta =V_r / V_w`
    C
    `tan theta =V_(rw)/sqrt(V_r^2+V_w^2)`
    D
    `tan theta =V_(r)/sqrt(V_r^2+V_w^2)`

  • A man is going due east with a velocity of 5ms^(-1) .It is vertically rainging downwards with a velocity of 4ms^(-1) .At what angle should he hold the umbrella to the vertical so as to protect him self from the rain?

    A
    `tan^(-1)(5/4)` in anti-clockwise direction
    B
    `tan^(-1)(5/4)` in clockwise direction
    C
    `tan^(-1)(5/4)`North of East
    D
    `tan^(-1)(5/4)`East of North

  • When it is raining vertically down, to a man walking on road the velocity of rain appears to be 1.5 times his velocity.To protect himself from rain he should hold the umbrealla at an angle theta to vertical. The tan theta=

    A
    `2/sqrt5`
    B
    `sqrt5/2`
    C
    `2/3`
    D
    `3/2`
    • NARAYNA-MOTION IN A PLANE-Level-Vi single answer
    1. An open merry go round rotates at an angular velocity omega.A person s...

      Text Solution

      |

    2. A standing man observes rain falling with the velocity of 20 m s^-1 at...

      Text Solution

      |

    3. A person standing on a road has to hold his umbrella at 60^(0) with th...

      Text Solution

      |

    4. Two swimmers leave point A on the bank of the river to reach point B l...

      Text Solution

      |

    5. A ball is thrown vertically upward from the 12 m level with an initial...

      Text Solution

      |

    6. From a point A on bank of a channel with still water a person must get...

      Text Solution

      |

    7. On morning Joy was walking on a grass-way in a garden.Wind was also bl...

      Text Solution

      |

    8. A projectile is fired with velocity v(0) from a gun adjusted for a max...

      Text Solution

      |

    9. A shot is fired with a velocity u at a very high vertical wall whose d...

      Text Solution

      |

    10. A stone is projected from the ground in such a direction so as to hit ...

      Text Solution

      |

    11. The benches of a gallery in a cricket stadium are 1 m wide and 1 m hig...

      Text Solution

      |

    12. If R is the horizontal range for theta inclination and h is the maximu...

      Text Solution

      |

    13. The acceleration of gravity can be measured by projecting a body upwar...

      Text Solution

      |

    14. A particle is released from a certain height H = 400m. Due to the wind...

      Text Solution

      |

    15. A fighter plane enters inside the enemy territory, at time t=0, with v...

      Text Solution

      |

    16. A bomber plane moving at a horizontal speed of 20 m//s releases a bomb...

      Text Solution

      |

    17. A body has maximum range R1 when projected up the plane. The same body...

      Text Solution

      |

    18. A particle P is projected from a point on the surface of smooth inclin...

      Text Solution

      |

    19. A particle is projected from surface of the inclined plane with speed ...

      Text Solution

      |

    20. A perfectly elastic particle is projected with a velocity v on a verti...

      Text Solution

      |