Gravitation class 11

Gravitational forces are:

• always attractive

• always repulsive

• sometimes attractive and sometimes repulsive

• None of these

A spherical planet far out in space has a mass M₀ and diameter . D₀ A particle of mass m falling freely near the surface of this planet will experience an acceleration due to gravity which is equal to:

• GM₀/ D₀²

• 4GM₀/ D₀²

• GM₀/ 2D₀²

• 4GM₀/ 3D₀²

The radii of two planets are respectively R₁ and R₂ and their densities are respectively ρ₁ and ρ₂ . The ratio of the accelerations due to gravity at their surfaces is:

• g₁ : g₂ = (ρ₁ / R₁) ∙ (ρ₂ / R₂)

• g₁ : g₂ = R₁R₂ : ρ₁ρ₂

• g₁ : g₂ = R₁ ρ₂ : R₂ ρ₁

• g₁ : g₂ = R₁ ρ₁ : R₂ ρ₂

The weight of body at earth's surface is W. At a depth half way to the centre of the earth, it will be (assuming uniform density in earth):

• W

• W /2

• W /4

• Zero

If g be the acceleration due to gravity at the earth surface, then what will be the increase in potential energy if object of mass m is raised by its radius R?

• 1/2mgR

• 2mgR

• mgR

• 1/4mgR

Tags

NGSS.HS-PS2-4

NGSS.HS-PS3-1

The escape velocity on a planet is v. If the radius of the planet contracts to 1/4th of present value without any change in its mass, The escape velocity will be

• halved

• doubled

• quadrupled

• one- fourth

Tags

NGSS.HS-PS2-4

The velocity with which a projectile , must be fired so that it escapes earth's gravitation, does not depend on

• mass of the earth

• mass of projectile

• radius of the projectile orbit

• gravitational constant

Tags

NGSS.HS-PS2-4

v_e and v_p denotes the escape velocity from the earth and another planet having twice the radius and the same mean density as the earth. Then

• v_p= v_e

• v_p = 2v_e

• v_p= 4 v_e

• 2v_p= v_e

Tags

NGSS.HS-PS2-4

Which satellite is earth synchronous satellite?

• Polar Satellite

• Geostationary Satellite

In the weightlessness state ,though the bodies have no weight but they do possess

• Inertia of mass

• Moment of inertia