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

The only force in each case is the force of gravity, (neglecting effects of air) equal to 0.5 N vertically downward. The answers do not change, even if the motion of the pebble is not along the vertical. The pebble is not at rest at the highest point. It has a constant horizontal component of velocity throughout its motion.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • LAW OF MOTION

    NCERT BANGLISH|Exercise EXERCISE (ADDITIONAL EXERCISE)|17 Videos

  • LAW OF MOTION

    NCERT BANGLISH|Exercise EXERCISE (ADDITIONAL EXERCISE)|17 Videos

  • KINETIC THEORY

    NCERT BANGLISH|Exercise ADDITIONAL EXERCISE|3 Videos

  • MECHANICAL PROPERTIES OF FLUIDS

    NCERT BANGLISH|Exercise EXERCISE|43 Videos

Similar Questions

Explore conceptually related problems

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 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) .

Knowledge Check

  • A stone of mass 0.05 kg is thrown in vertical by upward direction (take g = 10 m cdot s^(-2) ). Neglect air friction. The net force acting on the stone during its downwards motion is

    A
    0.5 N, upward
    B
    0.5 N, downward
    C
    5 N, upward
    D
    zero

  • A stone of mass 0.05 kg is thrown in vertical by upward direction (take g = 10 m cdot s^(-2) ). Neglect air friction. The net force acting on the stone during its upward motion is

    A
    0.5 N, upward
    B
    0.5 N, downward
    C
    5 N, upward
    D
    zero

    • Similar Questions

    Explore conceptually related problems

    Two bodies A and B of masses 5 kg and 10 kg in contact with each other rest on a table against a rigid wall . The coefficient of friction between the bodies and the table is 0.15. A force of 200 N is applied horizontally to A. What are (a) the reaction of the partition (b) the action-reaction forces between A and B ? What happens when the wall is removed? Does the answer to (b) change, when the bodies are in motion? Ignore the difference between mu_s and mu_k

    A 100 turn closely wound circular coil of radius 10 cm carries a current of 3.2 A. (a) What is the field at the centre of the coil? (b) What is the magnetic moment of this coil? The coil is placed in a vertical plane and is free to rotate about a horizontal axis which coincides with its diameter. A uniform magnetic field of 2T in the horizontal direction exists such that initially the axis of the coil is in the direction of the field. The coil rotates through an angle of 90^@ under the influence of the magnetic field. (c) What are the magnitudes of the torques on the coil in the initial and final position? (d) What is the angular speed acquired by the coil when it has rotated by 90^@ ? The moment of inertia of the coil is 0.1 kg m^2 .

    A constant force acting on a body of mass 3.0 kg changes its speed from 2.0 m s^(-1) to 3.5 m s^(-1) in 25 s. The direction of the motion of the body remains unchanged. What is the magnitude and direction of the force ?

    Two bodies A,B of masses 5 kg and 10 kg in contact with each other rest on a table against a rigid wall. The coefficient of friction between the bodies and the table is 0.15. A force of 200 N is applied horizontally to A. (i) What is the reaction of the partition? (ii) The actionreaction forces between A,B? (iii) What happens when the wall is removed ? Does the answer to (ii) change when bodies are in motion ? [ Ignore the difference between mu_(s) and mu_(k) ]

    Give the magnitude and direction of the net 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/h, (c ) just after it is dropped from the window of a train accelerating with 1 m s^(-2) , (d) lying on the floor of a train which is accelerating with 1 m s^(-2) , the stone being at rest relative to the train. Neglect air resistance throughout.

    Answer the following: (a) The top of the atmosphere is at about 400 kV with respect to 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 an electric shock as we step out of our house into the open? (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 1800 A 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) . Due to the slight conductivity of the atmosphere up to about 50 km (beyond which it is good conductor), about + 1800 C is pumped every second into the earth as a whole. The earth, however, does not get discharged since thunderstorms and lightning occurring continually all over the globe pump an equal amount of negative charge onthe earth.)

    Home
    Profile