Tag: application of newton's law of motion

Questions Related to application of newton's law of motion

An astronaut,inside an earth`s satellite experiences weightlessness because

physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

  1. he is falling freely

  2. no external force is acting on it

  3. no reaction is exerted by the floor of the satellite

  4. he is far away from the earth`s surface

Show answer
Correct Option: A
Explanation:

An astronaut,inside an earth`s satellite experiences weightlessness because he is falling freely.

so that the correct option is A.

Statement -1 :- A person feels weightlessness in an artificial satellite of the Earth. However a person on the Moon (natural satellite) feels his weight.
 and
 Statement - 2 :- Artificial satellite is a freely falling body and on the Moon surface, the weight is mainly due to Moon's gravitational attraction.

physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

  1. Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for statement-1

  2. Statement-1 is True, Statement-2 is True; Statement-2 is not a correct explanation for statement-1

  3. Statement-1 is true, Statement -2 is False

  4. Statement-1 is true, Statement -2 is True

Show answer
Correct Option: B

While orbiting around the earth in a apaceship, an astronaut experiences

physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

  1. more weight

  2. lesser weight

  3. weightlessness

  4. nothing at all

Show answer
Correct Option: C
Explanation:

  • When an astronaut is orbiting the earth, he is in a state of free fall along with the space vehicle, hence the astronaut is not able to exert his mass on its surface. This condition is called weightlessness condition.
  • Hence,option C is correct.


    • Motion of artificial satellite around the earth is powered by :

    physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

    1. Liquid fuel

    2. Solar energy

    3. Atomic energy

    4. None of these

    Show answer
    Correct Option: D
    Explanation:

    Answer is D.

    The orbit of an artificial earth satellite is an ellipse whose focus is at the center of the earth (in a particular case, a circle) and which maintains an unchanged position in space. Movement along such an orbit is called undisturbed motion and proceeds on the assumption that the earth attracts, according to Newtons law, like a sphere with spherical density distribution and that the satellite is affected only by the earths gravitational attraction.
    Such factors as atmospheric drag, compression of the earth, solar radiation pressure, and the attraction of the moon and sun are the reasons for deviations from undisturbed motion. Because of atmospheric drag, satellites in orbits at altitudes of several hundred kilometers gradually descend and, entering the dense layers of the atmosphere at an altitude of 120130 km and lower, disintegrate and burn up; thus, they exist for a limited period.
    Hence, the m    otion of artificial satellite around the earth is NOT powered by any of the options given.

    Which of the following is the cause of weightlessness experienced while orbiting around earth on a spaceship ?

    physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

    1. Inertia

    2. Zero gravity

    3. Acceleration

    4. Centre of gravity

    Show answer
    Correct Option: B
    Explanation:

    Weight of a body is due to its weight. A body becomes weightless when effective gravity on the body is zero.

    While orbiting around the earth in a spaceship, an astronaut weight becomes

    physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

    1. greater than their real weight

    2. lesser than their real weight

    3. zero

    4. infinity

    Show answer
    Correct Option: C
    Explanation:

    In a spaceship the astronaut weighs zero. Since there is no gravity in the space person feels weightless. Apart from these space is a vacuum and there is no air resistance and thus we feel weightless.

    Weightlessness in a satellite is experienced because 

    physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

    1. of inertia

    2. the gravitational force acting on the satellite is zero

    3. of centre of gravity

    4. centrifugal acceleration negates the acceleration due to gravity

    Show answer
    Correct Option: D
    Explanation:

    The satellite rotates in a circular path or elliptical path such that gravitational pull is always balanced by centrifugal force due to the rotational motion of satellite.

    Thus a body in the satellite will feel weightlessness.
    although force of gravity on a body is never zero but it is balanced by centrifugal force in  this case.
    so option D is correct.

    A satellite is orbiting the earth at 17,500 MPH, a rock is released from the satellite. Identify what would happen to the rock.

    physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

    1. The rock would orbit the earth at a velocity of 17,500 MPH next to the satellite

    2. As the rock cannot generate its own force, it will slow down

    3. Gravity will pull the rock towards earth

    4. As the rock is smaller than the satellite, it will accelerate and orbit at a greater velocity

    5. As the rock is smaller than the satellite, its inertia will pull it further away from earth

    Show answer
    Correct Option: A
    Explanation:

    The satellite moves in the orbit with a constant speed in circular path, with centripetal acceleration being provided by the force of gravity on it.

    The radius of orbit can be found by 
    $\dfrac{GMm}{R^2}=\dfrac{mv^2}{R}$
    $\implies R=\dfrac{GM}{v^2}$ which is independent of the mass of projectile(satellite)
    When the stone is released from the orbiting satellite, it moves with the same speed. Its mass is much lesser than that of satellite, but the orbital radius is independent of its mass, depending only upon the speed which is same. Thus is would also orbit the earth with same speed in same orbit as that of satellite.

    A man weighs $75 kg$ on the surface of the earth. His weight in a geostationary satellite is:

    physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

    1. infinity

    2. $150 kg$

    3. zero

    4. $75/2 kg$

    Show answer
    Correct Option: C
    Explanation:

    A geostationary satellite revolves around the earths with the same time period of earth's rotation, that is 24 hours.
    Since it revolves with same speed, the relative velocity is zero with respect to earth and hence any body inside a geostationary satellite doesn't feel the gravity.
    So, the weight would be equal to zero.

    A pendulum beats seconds on the earth. Its time period on a stationary satellite of the earth will be

    physics gravitation: planets and satellites weightlessness application of newton's law of motion escape velocity

    1. Zero

    2. $1\ s$

    3. $2\ s$

    4. Infinity

    Show answer
    Correct Option: D
    Explanation:

    Inside a satellite, every object experiences weightlessness

    Therefore Time period of a pendulum inside a satellite is $T= 2\pi \sqrt{\cfrac{L}{g}}$
    as $g=0$
    $\therefore T=\infty$ (Infinity)
    A pendulum beats seconds on the earth. Its time period on a stationary satellite of the earth will be Infinity.