Gravitation

Planets are moving around the Sun in

• elliptical orbits

• circular orbits

• parabolic

• none of these

The gravitational force between two bodies

• Is always attractive

• Is always repulsive

• Is inversely proportional to the distance between two bodies

• Is directly proportional to the distance between two bodies

The acceleration due to gravity depends

• Only on the mass of the planet

• Only on the size of the planet

• On both the size and mass of the planet

• None of these

The value of acceleration due to gravity g will be maximum at

• equatorial line

• the centre of earth

• the poles of Earth

• midway between the pole and the equator

A body is taken from the moon to the Earth.Which is correct?

• Mass decreases

• Mass increases

• Weight increases

• Weight decreases

In which case the escape velocity is maximum

• When angle of projection is 45°

• When it is projected vertically up

• When it is projected horizontally

• The escape velocity is independent of the angle of projection

The height of a geostationary Satellite from the surface of earth is

• 36000 m

• 36000 km

• 3600 m

• 3600 km

The moon has no atmosphere because

• Escape velocity is less than r.m.s velocity of gas molecules

• Escape velocity is greater than r.m.s. velocity of gas molecules

• Of low temperature on its surface

• Its high orbital velocity

The mass of a body on the earth surface is 40 kg. Its mass at the centre of earth will be

• Zero

• Greater than 40 kg

• Infinite

• Unchanged

The weight of a body at the surface of earth is 40 N. Its weight at the centre of earth will be

• Zero

• Infinite

• 40 N

• Unpredictable