Home
Class 11
PHYSICS
A pebble of mass 0.05 kg is thrown vert...

A pebble of mass 0.05 kg is thrown vertically upwards. Give the direction and magnitude of the net force on the pebble, (a) during its upward motion, (b) during its downward motion, (c) at the highest point where it is momentarily at rest. Do your answers change if the pebble was thrown at an angle of `45^@` with the horizontal direction? Ignore air resistance.

Text Solution

Verified by Experts

(a ) When marble is thrown in vertically upward direction gravitational acceleration is in downward direction
F= mg
`=0.49 N ` ( in downward direction)
( b) When marble (stone ) is moving in downward direction net force acting on it.
`F= mg`
`=0.05 xx 9.8`
=0.49 N (Downward direction )
(c ) At highest point marble is momentarily at rest in this condition resultant force acting on it is zero.
if marble is thrown at angle making `45^(@)` with horizontal then at highest point its horizontal component reamin constnat
Promotional Banner

Topper's Solved these Questions

  • LAW OF MOTION

    KUMAR PRAKASHAN|Exercise SECTION -B (ADDITIONAL EXERCISE )|17 Videos

  • LAW OF MOTION

    KUMAR PRAKASHAN|Exercise SECTION -B (NUMERICAL FROM DARPAN BASED ON TEXTBOOK)|8 Videos

  • LAW OF MOTION

    KUMAR PRAKASHAN|Exercise SECTION -B (NUMERICAL FROM TEXTUAL ILLUSTRATION)|12 Videos

  • GRAVITATION

    KUMAR PRAKASHAN|Exercise QUESTIONS PAPER Section - D|1 Videos

  • MACHANICAL PROPERTIES OF SOLIDS

    KUMAR PRAKASHAN|Exercise QUESTION PAPER|11 Videos

Similar Questions

Explore conceptually related problems

A ball is thrown vertically upwards. Which of the following plots represent the speed graph of the ball during its flight if the air resistence is not ignored?

A player throws a ball upwards with an initial speed of 29.4 ms^(-1) (a) What is the direction of acceleration during the upward motion of the ball ? (b) What are the velocity and acceleration of the ball at the highest point of its motion ? (c) Choose the x = 0 m and t=0 s to be the location and time of the ball at its highest point vertically downward direction to be the positive direction of x-axis and give the signs of position, velocity and acceleration of the ball during its upward and downward motion. (d) To what height does the ball rise and after how long does the ball return to the player's hands ? (Take g = 9.8 ms^(-2) and neglect air resistance).

A player throwsa a ball upwards with an initial speed of 29.4 ms^(-1) . (i) What is the direction of acceleration during the upwared motion of the ball? (ii) What are the velocity and acceleration of the ball at the highest point of its motion? (iii) Choose the x=0 and t=0 to be the location and time of the ball at its highest point, vertically downward direction to be the positive direction of X-axis, and give the signs of positive, velocity and acceleration of the ball during its upward, and downward motion. (iv) To what height does the ball rise and after how long does the ball return to the player's hand?( Take g =9.8 ms^(-2) , and neglect air resistance).

A ball of mass 0.5 kg thrown upwards reaches a maximum height of 5m.Calculate the work done by the force of gravity during this vertical displacement considering the value of g =10m//s^(2) .

When a particle is undergoing motion, the diplacement of the particle has a magnitude that is equal to or smaller than the total distance travelled by the particle. In many cases the displacement of the particle may actually be zero, while the distance travelled by it is non-zero. Both these quantities, however depend on the frame of reference in which motion of the particle is being observed. Consider a particle which is projected in the earth's gravitational field, close to its surface, with a speed of 100sqrt(2) m//s , at an angle of 45^(@) with the horizontal in the eastward direction. Ignore air resistance and assume that the acceleration due to gravity is 10 m//s^(2) . Consider an observer in frame D (of the previous question), who observes a body of mass 10 kg acelerating in the upward direction at 30 m//s^(2) (w.r.t. himself). The net force acting on this body, as observed from the ground is :-

When a particle is undergoing motion, the diplacement of the particle has a magnitude that is equal to or smaller than the total distance travelled by the particle. In many cases the displacement of the particle may actually be zero, while the distance travelled by it is non-zero. Both these quantities, however depend on the frame of reference in which motion of the particle is being observed. Consider a particle which is projected in the earth's gravitational field, close to its surface, with a speed of 100sqrt(2) m//s , at an angle of 45^(@) with the horizontal in the eastward direction. Ignore air resistance and assume that the acceleration due to gravity is 10 m//s^(2) . " A third observer (C) close to the surface of the reports that particle is initially travelling at a speed of 100sqrt(2) m//s making on angle of 45^(@) with the horizontal, but its horizontal motion is northward". The third observer is moving in :-

When a particle is undergoing motion, the diplacement of the particle has a magnitude that is equal to or smaller than the total distance travelled by the particle. In many cases the displacement of the particle may actually be zero, while the distance travelled by it is non-zero. Both these quantities, however depend on the frame of reference in which motion of the particle is being observed. Consider a particle which is projected in the earth's gravitational field, close to its surface, with a speed of 100sqrt(2) m//s , at an angle of 45^(@) with the horizontal in the eastward direction. Ignore air resistance and assume that the acceleration due to gravity is 10 m//s^(2) . There exists a frame (D) in which the distance travelled by the particle is minimum. This minimum distance is equal to :-

When a particle is undergoing motion, the diplacement of the particle has a magnitude that is equal to or smaller than the total distance travelled by the particle. In many cases the displacement of the particle may actually be zero, while the distance travelled by it is non-zero. Both these quantities, however depend on the frame of reference in which motion of the particle is being observed. Consider a particle which is projected in the earth's gravitational field, close to its surface, with a speed of 100sqrt(2) m//s , at an angle of 45^(@) with the horizontal in the eastward direction. Ignore air resistance and assume that the acceleration due to gravity is 10 m//s^(2) . The motion of the particle is observed in two different frames: one in the ground frame (A) and another frame (B), in which the horizontal component of the displacement is always zero. Two observers locates in these frames ill agree on :-

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod =15 cm, B =0.50 T, resistance of the closed loop containing the rod 9.0 m Omega . Assume the field to be uniform. (a) Suppose K is open and the rod is moved with a speed of 12 "cm s"^(-1) in the direction shown. Give the polarity and magnitude of the induced emf. (b) Is there an excess charge built up at the ends of the rods when K is open ? What if K is closed ? (c) With K open and the rod moving uniformly, there is no net force on the electrons in the rod PQ even though they do experience magnetic force due to the motion of the rod. Explain. (d) What is the retarding force on the rod when K is closed ? How much power is required (by an external agent) to keep the rod moving at the same speed (= 12 cm s^(-1) ) when K is closed ? How much power is required when K is open? (f)How much power is dissipated as heat in the closed circuit ? What is the source of this power ? (g) What is the induced emf in the moving rod if the magnetic field is parallel to the rails instead of being perpendicular ?

An object A is kept fixed at the point x= 3 m and y = 1.25 m on a plank p raised above the ground . At time t = 0 the plank starts moving along the +x direction with an acceleration 1.5 m//s^(2) . At the same instant a stone is projected from the origin with a velocity vec(u) as shown . A stationary person on the ground observes the stone hitting the object during its downward motion at an angle 45(@) to the horizontal . All the motions are in the X -Y plane . Find vec(u) and the time after which the stone hits the object . Take g = 10 m//s

KUMAR PRAKASHAN-LAW OF MOTION-SECTION -B (NUMERICAL FROM TEXTUAL EXERCISE)
  1. Give the magnitude and direction of the net force acting on (a) a drop...

    Text Solution

    |

  2. A pebble of mass 0.05 kg is thrown vertically upwards. Give the dire...

    Text Solution

    |

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

    Text Solution

    |

  4. One end of a string of length l is connected to a particle of mass m a...

    Text Solution

    |

  5. A constant retarding force of 50 N is applied to a body of mass 20 kg ...

    Text Solution

    |

  6. A constant force acting on a body of mass 3.0 kg changes its speed fro...

    Text Solution

    |

  7. A body of mass 5 kg is acted upon by two perpendicular forces 8 N and ...

    Text Solution

    |

  8. The driver of a three-wheeler moving with a speed of 36 km/h sees a ch...

    Text Solution

    |

  9. A rocket with a lift-off mass 20,000 kg is blasted upwards with an ini...

    Text Solution

    |

  10. A body of mass 0.40 kg moving initially with a constant speed of 10 m ...

    Text Solution

    |

  11. A truck starts from rest and accelerates uniformly at 2.0 m s^(-2). A...

    Text Solution

    |

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

    Text Solution

    |

  13. A man of mass 70 kg stands on a weighing scale in a lift which is movi...

    Text Solution

    |

  14. Shows the position-time graph of a particle of mass 4 kg. What is the ...

    Text Solution

    |

  15. Two bodies of m asses 10 kg and 20 kg respectively kept on a smooth, h...

    Text Solution

    |

  16. Two masses 8 kg and 12 kg are connected at the two ends of a light ine...

    Text Solution

    |

  17. A nucleus is at rest in the laboratory frame of reference. Show that i...

    Text Solution

    |

  18. Two billiard balls each of mass 0.05 kg moving in opposite directions ...

    Text Solution

    |

  19. A shell of mass 0.020 kg is fired by a gun of mass 100 kg. If the muz...

    Text Solution

    |

  20. A batsman deflects a ball by an angle of 45^(@) without changing its i...

    Text Solution

    |