Gravitation and Planetary Motion Quiz

Gravitation and Planetary Motion

• Gravitation is one of the four classes of interactions found in nature.

• Newton's Law of Gravitation states that gravitational force between two objects is proportional to the product of their masses and inversely proportional to the square of the distance between them.

• The value of G, the universal gravitational constant, is 6.67 x 10^-11 Nm^2kg^-2 and is same throughout the universe.

• Gravitational force is the weakest force in nature, and is 10^36 times smaller than electrostatic force and 10^18 times smaller than nuclear force.

• Acceleration due to gravity is the uniform acceleration produced in a freely falling object due to the gravitational pull of the earth, and is denoted by g.

• The value of g is independent of the mass of the object which is falling freely under gravity, and changes slightly from place to place.

• Gravitational field is the space in the surrounding of any body in which its gravitational pull can be experienced by other bodies.

• Gravitational potential at any point in gravitational field is equal to the work done per unit mass in bringing a very light body from infinity to that point.

• Geostationary or parking satellites appear to be at a fixed position at a definite height to an observer on earth, and are used in communication purposes.

• Escape velocity on earth is the minimum velocity with which a body has to be projected vertically upwards from the earth’s surface so that it just crosses the earth’s gravitational field and never returns.

• Weightlessness is achieved during freely falling under gravity, inside a space craft or satellite, at the centre of the earth, or when a body is lying in a freely falling lift.

• Kepler's Laws of Planetary Motion state that every planet revolves around the sun in elliptical orbit and the sun is at its one focus, the radius vector drawn from the sun to a planet sweeps out equal areas in equal intervals of time, and the square of the time period of revolution of planet around the sun is directly proportional to the cube semi-major axis of its elliptical orbit.Key Physics Concepts and Formulas

• Water will boil on the moon if a bottle of water at 30°C with a cork is opened on its surface.

• The orbital velocity of a satellite near Earth's surface is 8 km/s.

• The time period of a satellite near Earth's surface is approximately 84 minutes.

• The angular speed of a satellite near Earth's surface is 0.00125 rad/s.

• Inertial mass is equal to force divided by acceleration.

• Gravitational mass is equal to the weight of a body divided by acceleration due to gravity.

• Inertial and gravitational mass are equal in magnitude.

• The gravitational mass of a body is affected by the presence of other nearby bodies.

• The inertial mass of a body remains unaffected by the presence of other nearby bodies.

• These concepts and formulas are fundamental to understanding physics.

• They are used in a wide range of applications, from space exploration to everyday life.

• Understanding these concepts and formulas can help us better understand the world around us.