Home
Class 11
PHYSICS
During a heavy rain hailstones of averag...

During a heavy rain hailstones of average size 1.0 cm in diameter fall with an average speed of 20 m/s. Suppose 2000 hailstones strike every square meter of a `10mxx10m` roof perpendicularly in one second and assume that the hailstones do not rebound. Calculate the average force exerted by the falling hailstones on the roof. Density of a hailstone is `900 kg/m^3`

Text Solution

Verified by Experts

`d=1, cm, v=20 m/s,
`u=0, p=900 kg/m^3`
`0.9 gm/cm^3`
`volume=(4/3)pir^3`
`=4/3pi(0.5)^3[=0.5238 cm^3`
`:. Mass =up=0.5238xx0.9`
`:. Mass of 2000 halistone`
`=2000xx0.4714=947.857`
`:. ` rate of change of momentum per unit area
`=947.857xx2000`
`=19N/m^2`
`:.` total force exerted
`=19xx100=1900N`
Promotional Banner

Topper's Solved these Questions

  • CENTRE OF MASS, LINEAR MOMENTUM, COLLISION

    HC VERMA|Exercise Objective -2|11 Videos

  • CALORIMETRY

    HC VERMA|Exercise Exercises|18 Videos

  • CIRCULAR MOTION

    HC VERMA|Exercise Exercises|30 Videos

Similar Questions

Explore conceptually related problems

The hero of a stunt film fires 50 g bullets from a machine gun, each at a speed of 1.0 km/s. If he fires 20 bullets in 4 seconds. What average force does he exert against the machine gun during this period?

The 200 m free style women's swimming gold medal at Seol Olympic 1988 went to Heike Friendrich of East Germany when she set a new Olympic record of 1 minute and 57.56 seconds. Assume that she covered most of the distance with a uniform speed and had to exert 460 W to maintain her speed. Calculate the average force of resistance offered by the water during the swim.

A glass full of water has a bottom of area 20 cm^(2) , top of area 20 cm , height 20 cm and volume half a litre. Find the force exerted by the water on the bottom. Atmospheric pressure = 1.0 xx 10^(5) N//m^(2) . Density of water = 1000 kg//m^(-3) and g = 10 m//s^(2)

A circular coil of radius 8.0 cm and 20 turns is rotated about its vertical diameter with an angular speed of 50 rad s^(-1) in a uniform horizontal magnetic field of magnitude 3.0xx10^(-2)T . Obtain the maximum and average emf induced in the coil. If the coil forms a closed loop of resistance 10Omega , calculate teh maximum value of current in the coil Calculated the average power loss due to Joule heating. Where does this power come from?

A block of mas 2.0 kg is pulled up on a smooth incline of angle 30^0 with the horizontal. If the block moves wth an acceleration of 1.0 m/s^2 , find the power delivered by the pulling force at a time 4.0 s after the motion starts. What is the average power delivered during the 4.0 s after the motion starts?

A circular coil with cross - sectional area 0.1 cm^(2) is kept in a uniform magnetic field of strength 0.2 T. If the current passing in the coil is 3 A and plane of the loop is perpendicular to the direction of magnetic field . Calculate (a) total torque on the coil (b) total force on the coil (c ) average force on each electron in the coil due to the magnetic field of the free electron density for the material of the wire is 10^(28) m^(-3) .

The US athlete Florence Griffith oyner won the 100 m spring gold medal at Seol Olympic 1988 setting a new Olympic record of 10.54s. Assume that she achieved her maximum speed in a very short time and then ran the race with that speed till she crossed the line. Take her mas ot be 50 kg. a. Calculate the kinetic energy of Griffith Joyner at her full speed. b. Assuming tht the track the wind etc. offered an average resistance of one tenth of her weight, cfalculate the work done by the resistsnce durng the run. c. What power Griffith Joyner had to exet ot maintain uniform speed?

a. The top of the atmosphere is at about 400 kV with respectto the surface of the earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth, the field is about 100 Vm^(-1). Why then do we not get a electric shock as we step out of our house into the openy (Assume the house to be a steel cage so there is no field inside!) b. A man fixes outside his house one evening a two metre high insulating slab carrying on its top a large aluminium sheet of area 1m^(2) . Will he get an electric shock if he touches the metal sheet next morning? c. The discharging current in the atmosphere due to the small conductivity of air is known to be 1800A on an average over the globe. Why then does the atmosphere not discharge itself completely in due course and become electrically neutral? In other words, what keeps the atmosphere charged? d. What are the forms of energy into which the electrical energy of the atmosphere is dissipated during a lightning? (Hint: The earth has an electric field of about 100 Vm^(-1) at its surface in the downward direction, corresponding to a surface charge density =-10^(-9) Cm^(-2) ?.

HC VERMA-CENTRE OF MASS, LINEAR MOMENTUM, COLLISION-Exercises
  1. A block at rest explodes into three equal parts. Two parts start movin...

    Text Solution

    |

  2. Two fat astronauts each of mass 120 kg are travelling in a closed spac...

    Text Solution

    |

  3. During a heavy rain hailstones of average size 1.0 cm in diameter fall...

    Text Solution

    |

  4. A ball of mass m is dropped onto a floor from a certain height. The co...

    Text Solution

    |

  5. A man of mass 50 kg starts moving on the earth and acquires speed of 1...

    Text Solution

    |

  6. A gun is mounted on a railroad car. The mass of the car, the gun, the ...

    Text Solution

    |

  7. Two persns each of mass m are standing at the two extremes of a railro...

    Text Solution

    |

  8. Figure shows a small block of mass m which is started with a speed v o...

    Text Solution

    |

  9. IN a typical Indian Bugghi(a luxury cart drawn by horses), a wooden pl...

    Text Solution

    |

  10. A ball of mass 0.50 kg moving at a speed of 5.0 m/s collides with ano...

    Text Solution

    |

  11. A 60 kg man skating with a speed of 10 m/s collides with a 40 kg skate...

    Text Solution

    |

  12. consider a head on collision between two particles of masses m1 and m2...

    Text Solution

    |

  13. A bullet of mass m moving at a speed v hits a ball of mass M kept at r...

    Text Solution

    |

  14. A body of mass m moving with velocity v collides head on with another ...

    Text Solution

    |

  15. A block of mass 2.0 kg moving at 2.0 m/s collides head on with another...

    Text Solution

    |

  16. A particle of mass 100 g moving at an initial speed u collides with an...

    Text Solution

    |

  17. Two friends A and B (each weighing 40 kg) are sitting on a frictionles...

    Text Solution

    |

  18. A ball falls on the ground from a height of 2.0 m and rebounds up to a...

    Text Solution

    |

  19. In a gamma decay process, the internal energy of a nucleus of mass M d...

    Text Solution

    |

  20. A block of mass 2.0 kg is moving on a frictionless horizontal surface ...

    Text Solution

    |