Q (1): Assertion : Weight of a body on earth is not equal to the force with which the body is attracted towards the earth.

Reason : Weight of a body is dependent of the mass of the body.

  Q (2): Assertion : A sheet of paper falls slower, than one that is crumpled into a ball.

 Reason : Sheet of paper has large surface area, which causes it to face more opposing force caused by the environmental air.

Q (3): Assertion : The acceleration due to gravity on the moon is one-sixth that on the earth.

 Reason : The law of gravitation is the same on both the moon and the earth.

  Q (4): Assertion : Gravitational force between two particles is negligibly small compared to the electric force.

  Reason : The electric force is experienced by charged particles.

  Q (5): Assertion : If earth suddenly stop rotating about its axis, then the value of acceleration due to gravity will become same at all the places.

 Reason : The value of acceleration due to gravity is independent of rotation of earth.

  Q (6): Assertion : Gravitational potential of earth at every place on it is negative.

  Reason : Everybody on earth is bound by the attraction of earth.

  Q (7): Assertion : Space rockets are usually launched in the equatorial line from west to east.

 Reason : The acceleration due to gravity is minimum at the equator.

  Q (8): Assertion : The acceleration due to gravity increases with height above the earth's surface.

   Reason : Gravitational force decreases with height.

  Q (9): Assertion: Mass of an object is always zero.

  Reason: Mass of an object is the measure of its inertia and the substance contained by the body.

Q (10): Assertion: On moon, man feels lighter than earth.

 Reason: Due to more gravitational force exerted by moon on man.

  Q (11): Assertion: If the distance between two bodies of mass m1  , and m2 , is increased by a factor of 5, the gravitational force is reduced by  1/25

Reason: The gravitational force is inversely proportional to the square of the distance between two bodies.

  Q (12): Assertion: An object thrown vertically upward with certain velocity v, reaches maximum height and fall back with same velocity.

Reason: Whenever an object falls towards the earth, gravitational force of the earth causes acceleration.

  Q (13): Assertion : During a journey from the earth to the moon and back, maximum fuel is spent to overcome the earth’s gravity at take off.

Reason : Earth’s mass is much greater than that of the moon.

  Q (14): Assertion (A): When distance between two bodies is doubled and also mass of each body is doubled, gravitiational force between them becomes half.

Reason (R): According to Newton's law of gravitation, force is directly proportional to masses of the bodies and inversely proportional to square of distance between them.

  Q (15): Assertion (A): Earth is  attracted towards the object but with a very small acceleration.

  Reason (R): According to Newton's law of motion, if Earth attracts an object towards itself, then the object should also attract the Earth.

  Q (16): Assertion (A): The direction of acceleration is always towards the Earth.

 Reason (R): The value of "g" is 9.8  m/s2.  .

  Q (17): Assertion (A): The value of "g" is greater at the poles than at the equator.

 Reason (R): Radius is more at the equator than at the poles.

    Q (18): Assertion (A): An object experiences acceleration during free fall.

  Reason (R): Acceleration experienced by an object during free fall is independent of its mass.

  Q (38): Assertion (A): The S.I unit of weight is the same as that of force, that is, newton.

  Reason (R): As the weight of an object is the force with which it is attracted towards the earth.

  Q (20): Assertion (A): At the centre of Earth, a body has a centre of gravity but no centre of mass.

 Reason (R): Acceleration due to gravity at the centre of the Earth is zero.