Home
Class 12
PHYSICS
Give the magnitude and direction of the ...

Give the magnitude and direction of the net force acting on .
a drop of rain falling down with a constant speed.
(b) a cork of mass 10 g floating on water.
(c ) a kite skillfully held stationary in the sky.
(d) high-speed electron in space far from all material objects. Give the direction electric and magnetic fields.

Text Solution

Verified by Experts

(a) As the rain drop is falling with a constant speed, its acceleration a = 0. Hence net force F = ma = 0.
(b) As the cork is floating on water, its weight is being balanced by the upthrust (equal to weight of water displaced). Hence net force on the cork is zero.
(c ) As the kite is held stationary, net force on the kite is zero, in accordance with Newton.s first law.
(d) Force is being applied to overcome the force of friction. But as velocity of the car is constant, its acceleration.
a = 0. Hence net force on the car F = ma = 0.
(e ) As no field (gravitational / electric / magnetic) is acting on the electron, net force on it is zero.
Promotional Banner

Topper's Solved these Questions

  • LAWS OF MOTION

    AAKASH SERIES|Exercise Application|6 Videos

  • LAWS OF MOTION

    AAKASH SERIES|Exercise EXERCISE - I|157 Videos

  • LAWS OF MOTION

    AAKASH SERIES|Exercise QUESTIONS FOR DESCRIPTIVE ANSWER|5 Videos

  • GEOMETRICAL OPTICS

    AAKASH SERIES|Exercise ADDITIONAL PRACTICE EXERCISE (LEVEL-II PRACTICE SHEET (ADVANCED) INTEGER TYPE QUESTIONS)|10 Videos

  • LOGIC GATES

    AAKASH SERIES|Exercise Exercise (Very Short Answer)|10 Videos

Similar Questions

Explore conceptually related problems

Give the magnitude and direction of the net force acting on a Cork of mass 10 g floating on water

Give the magnitude and direction of the net force acting on (a) a drop of rain falling down with a constant speed (b) a cork of mass 10 g floating on water (c) a kite skillfully held stationary in the sky (d) a car moving with a constant velocity of 30 kh//h on a rough road (e) a high speed electron in space free from all gravitational objects and free of electric and magnetic fields.

Give the magnitude and direction of the net force acting on a kite skillfully held stationary in the sky

Give the magnitude and direction of the net force acting on a high - speed electron in space far from all material objects, and free of electric and magnetic field .

Give the magnitude and direction of the force acting on a stone of mass 0.1 kg (a) just after it is dropped from the window of a stationary train (b) just after it is dropped from the window of a train running at a constant velocity of 36 km//hr (c) just after it is dropped from the window of a train accelerating with 1 ms^(-2) (d) lying on the floor of a train which is accelerating with 1 ms^(-2) the stone being at rest relative to the train . Neglect the resistance of air throughout .

A current i, indicated by the crosses in figure, is established in a strip of copper of height h and width w. A uniform field of magnetic induction B is applied at right angle to the strip. (a) Calculate the drift velocity v_d of the electrons. (b) What are the magnitude and direction of the magnetic force F acting on the electrons? (c) What should the magnitude and direction of a homogeneous electric field E be in order to counterbalance the effect of mangetic field? (d) Calculate voltage V necessary between two sides of the conductor in order to creat this field E Between which sides of the conductor would this voltage have to be applied? (e) If no electric field is applied from the outside, the electrons will be pushed somewhat to one side and therefore will give rise to a uniform electric field E_H across the conductor until the forces of this electrostatic field E_H balance the magnetic forces encountered in part (b). What will be the magnitude and direction of field E_H ? Assume that n, the number of conductor electrons per unit volume is 1.1xx10^(29) m^-3, h = 0.02 m, w= 0.1 cm, i = 50 A, and B=2 T.

A square shaped, conducting wire loop of side L , total mass m and total resistance R initially lies in the horizontal x-y plane, with corners at (x, y, z) = (0,0,0), (0, L , 0), (L, 0 ,0), and (L, L, 0) . There is a uniform upward magnetic field in the space within and around the loop. The side of the loop that extends from (0, 0, 0)to (L, 0, 0) is held in place on the x-axis, the rest of the loop is released, it begins to rotate due to the gravitational torque. (a) Find the net torque (magnitude and direction)that acts on the loop when it has rotated through an anglr phi from its original orientation and is rotating dounward at an angular speed omega . (b) Find the angular acceleration of the loop at the instant described in part (a). ( c) Compared to teh case with zero magnetic field, does it take the loop a longer or shorter time to rotate through 90^(@) ? Explain. (d) Is mechanical energy conserved as the loop rotates downward ? Explain.

A velocity filter uses the properties of electric and magnetic field to select particles that are moving with a specifice velocity. Charged particles with varying speeds are directed into the filter as shown. The filter consistt of an electric field E and a magnetic field B, each of constant magnitude, directed perpendicular to each other as shown, The charge particles will experience a force due to electric field given by F = qE. If positively charged particles are used, this force is towards right. The moving particle will also experience a force due to magnetic field given by F = qvB . When forces due to the two fields are of equal magnitude, the net force on the particle will be zero, the particle will pass through centre with its path unaltered. The electric and magnetic fields can be adjusted t choose the specific velocity to be filtered. The efect of gravity can be neglected. The electric and magnetic fields are adjusted to detect particles with positive charge q of certain speed v_(0) . which of the following expressions is equal to this speed?

The Betatron was the first important machine for producing high energy electrons. The action of the betatron depends on the same fundamental principle as that of the transformer in which an alternating current applied to a primary coil induces an altermating current usually with higher or lower voltage in the secondary coil. In the betatron secondary coil is replaced by a doughnut shaped vacuum chamber.Electron produced in the doughnut from a hot filament, are given a preliminary acceleration by the application of an electric field having potential difference of 20 kV to 70 kV , when an alternating magnetic field is applied parallel to the axis of the tube, two effects are produced (1) an electromotive force is produced in the electron orbit by the changing magnetic flux that gives an additional energy to the electrons (2) a radial force is produced by the action of magnetic field whose direction is perpendicular to the electron velocity. Which keeps the electron moving in a circular path. Conditions are arranged such that the increasing magnetic field keeps the electron in a circular orbit of constant radius. The mathematical relation between the betatron parameters to ensure the above condition is called BETATRON condition. If the orbit radius of the circular path traced by the electron is R , magnetic field is B , speed of the electron is v , mass of the electron is m , charge on the electron is e and phi is the flux within the orbit of radius R . Then answer the following questions based on the above comprehension. What is the tangential force acting on the electron ?

The Betatron was the first important machine for producing high energy electrons. The action of the betatron depends on the same fundamental principle as that of the transformer in which an alternating current applied to a primary coil induces an altermating current usually with higher or lower voltage in the secondary coil. In the betatron secondary coil is replaced by a doughnut shaped vacuum chamber.Electron produced in the doughnut from a hot filament, are given a preliminary acceleration by the application of an electric field having potential difference of 20 kV to 70 kV , when an alternating magnetic field is applied parallel to the axis of the tube, two effects are produced (1) an electromotive force is produced in the electron orbit by the changing magnetic flux that gives an additional energy to the electrons (2) a radial force is produced by the action of magnetic field whose direction is perpendicular to the electron velocity. Which keeps the electron moving in a circular path. Conditions are arranged such that the increasing magnetic field keeps the electron in a circular orbit of constant radius. The mathematical relation between the betatron parameters to ensure the above condition is called BETATRON condition. If the orbit radius of the circular path traced by the electron is R , magnetic field is B , speed of the electron is v , mass of the electron is m , charge on the electron is e and phi is the flux within the orbit of radius R . Then answer the following questions based on the above comprehension. What is the value of (d(m|vecv|))/(dt) ?

AAKASH SERIES-LAWS OF MOTION-Problem
  1. The variation of momentum with time of one of the body in a two body c...

    Text Solution

    |

  2. A particle of mass 1 g moves on a straight line. The variation of its ...

    Text Solution

    |

  3. Give the magnitude and direction of the net force acting on . a drop...

    Text Solution

    |

  4. A pebble of mass 0.05 kg is thrown vertically upwards. Give the direct...

    Text Solution

    |

  5. Give the magnitude and direction of the net force acting on a stone of...

    Text Solution

    |

  6. A bob of mass 0.1 kg hung from the ceiling of a room by a string 2 m l...

    Text Solution

    |

  7. A body of mass 2kg has an initial speed 5 m/s. A force acts as it for ...

    Text Solution

    |

  8. A particle of mass 120 g moving at speed of 750 cm/s is acted upon by ...

    Text Solution

    |

  9. A bullet is fired from a gun . The force on the bullet is given by ...

    Text Solution

    |

  10. particle of mass m, moving with velocity 'u' makes head on collision w...

    Text Solution

    |

  11. Figure 5.16 shows the position-time graph of a particle of mass 4 kg. ...

    Text Solution

    |

  12. A ball of sqrt(3)xx10^(-2)kg hits a hard surface at 45^(@) to normal w...

    Text Solution

    |

  13. A gardener is watering plants at the rate 0.1 litre/sec using a pipe o...

    Text Solution

    |

  14. The linear momentum of a particle varies with times as p=a(0)+at+bt^(...

    Text Solution

    |

  15. Liquid of density rho flows along a horizontal pipe of uniform area of...

    Text Solution

    |

  16. System is shown in the figure. Velocity of sphere A is 9 (m)/(s). Find...

    Text Solution

    |

  17. Explain why a horse cannot pull a cart and run in empty space

    Text Solution

    |

  18. Two ice skaters A and B approach each other at right angles. A has mas...

    Text Solution

    |

  19. A man of mass m climbs a rope of length L suspended below a balloon of...

    Text Solution

    |

  20. A dog of mass 10 kg is standing on a flat 10 m long boat so that it is...

    Text Solution

    |