STD-IX, CBSE BOARD, NCERT BOOK, IMPORTANT MCQs ON "MASS AND WEIGHT"

1.  Mass of an object is-

(a) amount of matter present in the object

(b) same as weight of an object

(c) measure of gravitational pull

(d) none of these

 

ANS: amount of matter present in the object

 

2.  SI unit of mass is-

(a) gram

(b) kg

(c) quintal

(d) ton

 

ANS: kg

 

3.  Which of the following is correct for mass?

(a) It is a vector quantity

(b) It is not a fundamental property of material body.

(c) It is the force with which the earth attracts a body.

(d) It is the quantity of matter contained in a body.

 

ANS: It is the quantity of matter contained in a body

 

4.  If more force is required to bring a body into a unit acceleration, the body has

(a) less mass

(b) zero mass

(c) more mass

(d) mass is independent of force

 

ANS: more mass

 

5.  Which of the following statements is/are correct?

I. Mass of an object is the measure of its inertia

            II. Heavier the object smaller is the inertia

            III. The mass of an object is variable

(a) Only I

(b) I and III

(c) II and III

(d) I and II

 

ANS: Only I

 

6.  The mass of a body is measured to be 12 kg on the earth. If it is taken to the moon, its mass will be-

(a) 12 kg

(b) 6 kg

(c) 2 kg

(d) 72 kg

 

ANS: 12 kg

 

7.  If the mass of a boy on the surface of the earth is 30 kg, then his mass on the surface of the moon will be-

(a) 5 kg

(b) 30 kg

(c) 180 kg

(d) zero

 

ANS: 30 kg

 

8.  The mass of a body is M on the earth’s surface. What is the mass of the same body on the moon’s surface?

(a) M

(b) M/6

(c) Zero

(d) M/2

 

ANS: M

 

9.  The mass of an astronaut on the surface of the earth is 60 kg. The ratio of the mass of the astronaut on the surface of earth and on the surface of the moon will be-

(a) 1:6

(b) 6:1

(c) 2:1

(d) 1:1

 

ANS: 1:1

 

10.  The weight of an object is-

(a) the quantity of matter it contains

(b) refers to its inertia

(c) same as its mass but is expressed in different units

(d) the force with which it is attracted towards the earth

 

ANS: the force with which it is attracted towards the earth

 

11.  Weight of an object depends on-

(a) temperature of the place

(b) atmosphere of the place

(c) mass of an object

(d) none of these

 

ANS: mass of an object

 

12.  SI unit of weight is-

(a) kg

(b) dyne

(c) newton

(d) metre

 

ANS: newton

 

13.  Which of the following is correct?

(a) Weight is a scalar quantity

(b) Weight is not a fundamental quantity

(c) Weight does not depend on acceleration due to gravity

(d) None of these

 

ANS: Weight is not a fundamental quantity

 

14.  What is the mass of an object whose weight is 49 N on the earth?

(a) 5 kg

(b) 20 kg

(c) 15 kg

(d) 12 kg

 

ANS: 5 kg

 

15.  The weight of a rock on the moon is 200.6 N. What is its mass on the earth?

(a) 20 kg

(b) 118 kg

(c) 200 kg

(d) 1180 kg

 

ANS: 118 kg

 

16.  An object of mass m is taken to the moon from the earth-

(a) Mass and weight of the object will be same as on the earth

(b) mass of the object decreases but its weight will remain the same on the moon

(c) mass of the object increases but its weight will remain the same on the moon

(d) mass of the object remains the same but its weight decreases on the moon

 

ANS: Mass of the object remains the same but its weight decreases on the moon

 

17.  The weight of a body is 120 N on the earth. If it is taken to the moon, its weight will be about,

(a) 120 N

(b) 60 N

(c) 20 N

(d) 720 N

 

ANS: 20 N

 

18.  The weight of a man on the surface of moon is 300 N. The weight of this man on the surface of the earth is-

(a) 300 N

(b) 5 N

(c) 50 N

(d) 1800 N

 

ANS: 1800 N

 

19.  If a planet existed whose mass was twice that of Earth and whose radius is 3 times greater, how much will a 1 kg mass weigh on the planet?

(a) 25 N

(b) 2.17 N

(c) 1.1 N

(d) 5 N

 

ANS: 2.17 N

 

20.  Consider a heavenly body which has a mass twice that of the earth and a radius thrice that of the earth. The weight of a book on this heavenly body, if its weight on the earth is 900 N will be:

(a) 400 N

(b) 600 N

(c) 500 N

(d) 200 N

 

ANS: 400 N

 

21.  The weight of a body cannot be expressed in-

(a) kg wt

(b) N

(c) dyne

(d) kg

 

ANS: kg

 

22.  10 kg wt is equal to-

(a) 9.8 N

(b) 98 N

(c) 980 N

(d) 1/9.8 N

 

ANS: 98 N

 

23.  For no change in the mass of the earth, if its radius is halved the weight of an object of mass 10 kg will be:

(a) 40 kg wt

(b) 10 kg wt

(c) 80 kg wt

(d) 20 kg wt

 

ANS: 40 kg-wt

 

24.  What is the weight of a 7 kg-wt body in a planet whose mass is 1/7 of that of earth and radius is ½ of the earth?

(a) 4 kg-wt

(b) 8 kg-wt

(c) 7 kg-wt

(d) 2 kg-wt

 

ANS: 4 kg-wt

 

25.  The weights of three objects X, Y and Z measured on three celestial bodies are listed in the box (g on the Moon, Jupiter and Mercury are 1.7 ms^-2, 25.4 ms^-2 and 3.8 ms^-2 respectively).

Object X on the Moon is 340 N

Object Y on Jupiter is 6096 N

Object Z on Mercury is 399 N

Which of the following sequences show X, Y and Z in ascending order of their masses?

(a) X, Y, Z

(b) Z, X, Y

(c) X, Z, Y

(d) Y, Z, X

 

ANS: Z, X, Y

 

26.  If the earth shrinks half in radius, its mass remaining the same, then by what percentage will the weight of an object on earth change?

(a) decreases by 50%

(b) increases by 50%

(c) decreases by 25% 

(d) increases by 300%

 

ANS: increases by 300%

 

27.  The weight of an object-

(a) increases when taken from the pole to the equator

(b) increases when taken from the equator to the pole

(c) increases when taken from Delhi to the top of Mount Everest

(d) increases when taken from the surface of the earth to moon

 

ANS: increases when taken from the equator to the pole

 

28.  Arun buys 5 gram of gold at the poles. The weight of the gold at the equator will be-

(a) 5 g

(b) less than 5 g

(c) greater than 5 g

(d) 5.5 g

 

ANS: less than 5 g

 

29.  A person weighs W at Delhi. The weight of the person on the peak of Mount Everest will be-

(a) = W 

(b)  > W

(c)  < W

(d) zero

 

ANS: < W

 

30.  A person weighs W on the surface of the earth. The weight of the person at the centre of the earth will be-

(a) < W

(b) > W

(c) = W

(d) Zero

 

ANS: Zero

 

31.  A person can jump upto 5 feet on the surface of the earth. On the surface of the moon, the same person can jump-

(a) = 5 ft

(b) < 5 feet

(c) > 5 feet

(d) as much as he wants

 

ANS: > 5 feet

 

32.  Weight of an astronaut on the surface of the earth is W₁ and his weight on the surface of the moon is W₂. The ratio W₁/W₂ will be-

(a) 1:6

(b) 6:1

(c) 1:1

(d) 36:1

 

ANS: 6:1

 

33.  In spaceship moving in space, person experience weightlessness as the value of,

(a) mass is zero

(b) acceleration due to gravity is zero

(c) gravitational force is zero

(d) none of these

 

ANS: acceleration due to gravity is zero

 

34.  Consider an elevator moving downwards with an acceleration a, the force exerted by a passenger of mass m on the floor of the elevator is-

(a) ma

(b) ma - mg

(c) mg - ma

(d) mg + ma

 

ANS: ma - ma

 

35.  If an elevator is moving vertically up with an acceleration a, the force exerted on the floor by a passenger of mass m is-

(a) mg

(b) ma

(c) mg - ma

(d) mg + ma

 

ANS: mg + ma

 

STD-IX, CBSE BOARD, NCERT BOOK, GRAVITATION, MCQs ON ACCELERATION DUE TO GRAVITY (g)

1.  When a body is thrown up, the force of gravity is-

(a) in the upward direction

(b) in the downward direction

(c) zero

(d) in the horizontal direction

 

ANS: in the downward direction

 

2.  When an object is thrown up, the force of gravity-

(a) is opposite to direction of motion

(b) is in the same direction of motion

(c) becomes zero at the highest point

(d) increases as it rises up

 

ANS: is opposite to the direction of motion

 

3.  In vacuum, all freely falling objects-

(a) have the same speed

(b) have the same velocity

(c) have the same force

(d) have the same acceleration

 

ANS: have the same acceleration

 

4.  Choose the correct statement.

(a) all bodies repel each other in the universe

(b) our earth does not behave like a magnet

(c) acceleration due to gravity is 8.9 ms^-2

(d) all bodies fall at the same rate in vacuum

 

ANS: all bodies fall at the same rate in vacuum

 

5.  A heavy stone falls (if air resistance is neglected)-

(a) faster than a light stone

(b) slower than a light stone

(c) with same acceleration as a light ball falls

(d) none of these

 

ANS: with same acceleration as a light ball falls

 

6.  Two bodies A and B of mass 500 g and 200 g respectively are dropped near the earth’s surface. Let the acceleration of A and B be a_A and a_B respectively, then-

(a) a_A = a_B

(b) a_A > a_B

(c) a_A < a_B

(d) can’t say

 

ANS: a_A = a_B

 

7.  Two iron and wooden balls identical in size are released from the same height in vacuum. The time taken by them to reach the ground are-

(a) not equal

(b) exactly equal

(c) may or may not be equal

(d) zero

 

ANS: exactly equal

 

8.  A sheet of paper and another sheet of paper crumpled into a ball are dropped from the top of a tower-

(a) sheet of paper reach the ground earlier than the ball

(b) sheet of paper reach the ground later than the ball

(c) both sheet of paper and ball reach the ground simultaneously

(d) sheet of paper remains in the air

 

ANS: sheet of paper reach the ground later than the ball

 

9.  The acceleration due to gravity near the moon’s surface is-

(a) approximately equal to that near the earth’s surface

(b) approximately six time that near the earth’s surface

(c) approximately one-sixth of that near the earth’s surface

(d) slightly greater than that near the earth’s surface

 

ANS: approximately one-sixth of that near the earth’s surface

 

10.  The acceleration due to gravity is g_e on Earth and g_m on Moon-

(a) g_e = g_m

(b) g_e < g_m

(c) g_e = g_m/6

(d) g_m = g_e/6

 

ANS: g_m = g_e/6

 

STD-IX, NCERT, CBSE BOARD, GRAVITATION, MCQs

1.  A boy is whirling a stone tied with a string in a horizontal circular path. The string breaks, the stone-

(a) will continue to move in the circular path

(b) will move along a straight line towards the centre of the circular path

(c) will move along a straight line tangential to the circular path

(d) will move along a straight line perpendicular to the circular path away from the boy

 

ANS: will move along a straight line tangential to the circular path (it is due to inertia of motion)

 

2.  Neglecting rotation of the earth, if suddenly the attractive power of the earth drops to zero, a man standing on the earth will

(a) fly up                                                                      

(b) slide along the surface

(c) move out tangentially

(d) stand unaffected

 

ANS: move out tangentially

 

3.  If suddenly the gravitational force of attraction between earth and a satellite revolving around it becomes zero, then the satellite will-

(a) continue to move in its orbit with same velocity

(b) move tangentially and escape away

(c) become stationary in its orbit

(d) move towards the Earth

 

ANS: move tangentially and escape away

 

4.  The universal law of gravitation was proposed by

(a) Copernicus

(b) Newton

(c) Galileo

(d) Archimedes

 

ANS: Newton

 

5. Newton’s law of gravitation is valid-

(a) on the earth only

(b) on the moon only

(c) in the laboratory only

(d) everywhere

 

ANS: everywhere

 

6.  Newton’s Law of gravitation:

(a) can be verified in the laboratory

(b) cannot be verified but is true

(c) is valid only on Earth

(d) is valid only in the solar system

 

ANS: can be verified in the laboratory

 

7.  Law of gravitation is applicable for-

(a) heavy bodies only

(b) medium sized bodies only

(c) small sized bodies only

(d) bodies of any size

 

ANS: bodies of any size

 

8.  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

 

ANS: any two bodies having some mass

 

9.  The type of force which exists between charged bodies is-

(a) only gravitational

(b) neither gravitational

(c) only electrical

(d) both electrical and gravitational

 

ANS: both electrical and gravitational

 

10.  The gravitational force is-

(a) the weakest force

(b) the strongest force

(c) a short-range force

(d) non-central force

 

ANS: the weakest force