CLASS IX GRAVITATION

The value of acceleration due to gravity

• (a) is same on equator and poles

• (b) is least on poles

• (c) is least on equator

• (d) increases from pole to equator

The gravitational force between two objects is F. If masses of both objects are halved without changing distance between them, then the gravitational force would become

• (a) F/4

• (b) F/2

• (c) F

• (d) 2F

Law of gravitation gives the gravitational force between

• (a) the earth and a point mass only

• (b) the earth and Sun only

• (c) any two bodies having some mass

• (d) two charged bodies only

Tags

NGSS.HS-PS2-4

The value of quantity G in the law of gravitation

• (a) depends on mass of earth only

• (b) depends on radius of earth only

• (c) depends on both mass and radius of earth

• (a) is independent of mass and radius of the earth

The earth attracts a body of mass 1 kg on its surface with a force of

• (a) 9.8 N

• (b) 19.6 N

• (c) 6.67 x 10^–11 N

• (d) 2 x 6.67 x 10^–11 N

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

The atmosphere is held to the earth by

• (a) gravity

• (b) wind

• (c) clouds

• (d) earth’s magnetic field

Tags

NGSS.HS-PS2-4

The force of attraction between two unit point masses separated by a unit distance is called

• (a) gravitational potential

• (b) acceleration due to gravity

• (c) gravitational field

• (d) universal gravitational constant

The weight of an object at the centre of the earth of radius R is

• (a) zero

• (b) infinite

• (c) R times the weight at the surface of the earth

• (d) 1/R² times the weight at surface of the earth

The mass of a body on the surface of earth is 12 kg. If acceleration due to gravity on moon is 1/6 of acceleration due to gravity on earth, then its mass on moon will be

• (a) 2kgf

• (b) 72kg

• (c) 12kg

• (d) zero

A stone dropped from a building takes 4 s to reach the ground. The height of the building is

• (a) 19.6 m

• (b) 80.4 m

• (c) 78.4 m

• (d) 156.8 m