Home
Class 12
PHYSICS
STATEMENT-1 : Assuming sun to be a body ...

STATEMENT-1 : Assuming sun to be a body of very large mass in comparison to all other planets, the angular momentum of all the planets about the sun remains conserved.
because
STATEMENT-2 : Gravitational force is always conservative.

A

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-1

B

Statement-1 is True, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-1

C

Statement-1 is True , Statement-2 is False

D

Statement-1 is False , Statement-2 is True

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze both statements and their implications regarding angular momentum and gravitational forces. ### Step-by-Step Solution: **Step 1: Understanding Statement 1** - The statement asserts that the angular momentum of all planets about the sun remains conserved, assuming the sun has a very large mass compared to the planets. - Angular momentum (\(L\)) for a planet in orbit around the sun can be expressed as: \[ L = mvr \] where \(m\) is the mass of the planet, \(v\) is its tangential velocity, and \(r\) is the distance from the sun. **Hint for Step 1:** Recall the definition of angular momentum and how it relates to mass, velocity, and radius. **Step 2: Applying Kepler's Laws** - According to Kepler's laws, particularly the second law, a line segment joining a planet and the sun sweeps out equal areas during equal intervals of time. This implies that the planet's speed varies depending on its distance from the sun. - When a planet is closer to the sun, it moves faster, and when it is farther away, it moves slower. This variation in speed maintains the conservation of angular momentum. **Hint for Step 2:** Think about how the area swept out by the planet relates to its velocity and distance from the sun. **Step 3: Understanding Statement 2** - Statement 2 claims that the gravitational force is always conservative. A conservative force is one where the work done in moving an object between two points is independent of the path taken. - The gravitational force meets this criterion, as the work done by gravity in a closed path is zero. **Hint for Step 3:** Recall the definition of conservative forces and how gravitational force fits into this category. **Step 4: Analyzing the Relationship Between the Statements** - While both statements are correct, the second statement does not provide a direct explanation for the first statement. - The conservation of angular momentum in the context of gravitational forces is due to the absence of external torques acting on the system, which is a consequence of the gravitational force being central and conservative. **Hint for Step 4:** Consider whether the explanation provided by Statement 2 directly supports the conclusion of Statement 1. **Step 5: Conclusion** - Both statements are true: - Statement 1 is true because the angular momentum of planets about the sun is conserved due to the nature of their orbits and the large mass of the sun. - Statement 2 is true because gravitational force is a conservative force. - However, Statement 2 does not explain Statement 1 directly. ### Final Answer: Both statements are true, but Statement 2 is not the correct explanation for Statement 1.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • GRAVITATION

    FIITJEE|Exercise Assigment problems (Objective) (level-II)|20 Videos
  • GRAVITATION

    FIITJEE|Exercise Numerical based Question|2 Videos
  • GRAVITATION

    FIITJEE|Exercise Assigment problems (Objective) (level-I)|50 Videos
  • GMP ASSESMENT

    FIITJEE|Exercise Numerical Based|61 Videos
  • HEAT AND TEMPERATURE

    FIITJEE|Exercise NUMERICAL BASES QUESTIONS|1 Videos

Similar Questions

Explore conceptually related problems

STATEMENT-1 : In an elastic collision between two balls, the total kinetic energy of the two bodies does not remain conserved during the collision. and STATEMENT-2 : As the balls collide, they compress each other.

All the planets and other celestial objects of our solar system are bound to the Sun due to its ___ force.

Knowledge Check

  • Assertion: Linear momentum of a planet does not remain conserved. Reason: Gravitational force acts on it.

    A
    If both assertion and reason are true and reason is the correct explanation of assertion.
    B
    If both assertion and reason are true but reason is not the correct explanation of assertion.
    C
    If assertion is true but reason is false.
    D
    f both assertion and reason are false.
  • A: The speed of a planet is maximum at perihelion . R : The angular momentum of a planet about centre of sun is conserved .

    A
    If both Assertion & Reason are true . And the reason is the correct explanation of the assertion , then mark (1)
    B
    If both Assertion & Reason are true but the reason is not the correct explanation of the assertion , then mark (2)
    C
    If Assertion is true statement but Reason is false , then mark (3)
    D
    It will move the same speed , tangentially to the spacecraft
  • A : Angular momentum of a satellite about a planet is constant . R :Gravitational force is a central force so its torque about the sun is zero .

    A
    If both Assertion & Reason are true . And the reason is the correct explanation of the assertion , then mark (1)
    B
    If both Assertion & Reason are true but the reason is not the correct explanation of the assertion , then mark (2)
    C
    If Assertion is true statement but Reason is false , then mark (3)
    D
    It will move the same speed , tangentially to the spacecraft
  • Similar Questions

    Explore conceptually related problems

    STATEMENT -1 : Kepler's second law is the consequence of law of conservation of angular momentum. STATEMENT -2 : In planetary motion, the momentum, angular momentum and mechanical energy is conserved. STATEMENT -3 : The gravitational field of a circular ring is maximum at a point upon axis at distance (R )/(sqrt(2)) from the centre, where R is the radius of ring.

    Assertion : In planetary motion angular momentum of planet about centre of sun remains constant. But linear momentum of system does not remain constant. Reason : Net torque on planet any point is zero.

    For a planet moving and the sun in an elliptical orbit, which of the following quantities remain constant? (i) The total energy of the 'sun plus planet' system (ii) The angular momentum of the planet about the sun (iii) The force of attraction between the two (iv) The linear momentum of the planet

    Astronomers observe two separate solar systems each consisting of a planet orbiting a sun. The two orbits are circular and have the same radius R . It is determined that the planets have angular momenta of the same magnitude L about their suns, and that the orbital periods are in the ratio of three to one, i.e. T_(1)=3T_(2) . The ratio m_(1)//m_(2) of the masses of the two planets is

    STATEMENT -1 : In absence of air friction, it is claimed that all object fall with the same acceleration although, a heavier object is pulled towards the earth with more force than a lighter object. because STATEMENT-2 : Net external force is always equal to rate of change of linear momentum.