Chapter 3 MCQs

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

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1

Which statement about mass is correct?

A Mass is the force of gravity on an object.
B Mass is measured using a force meter.
C Mass is the quantity of matter in an object.
D Mass changes when gravitational field strength changes.

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2

Which statement about weight is correct?

A Weight is a scalar quantity.
B Weight is measured in kilograms.
C Weight is the gravitational force acting on an object.
D Weight is the same everywhere in the Universe.

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3

An object has a mass of 5.0 kg. The gravitational field strength is 9.8 N/kg.

What is the weight of the object?

A 0.51 N
B 4.8 N
C 49 N
D 98 N

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4

An object has a weight of 196 N on Earth. Take g = 9.8 N/kg.

What is its mass?

A 0.050 kg
B 20 kg
C 186 kg
D 1921 kg

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5

The gravitational field strength on a planet is 4.0 N/kg. An object has mass 12 kg.

What is the weight of the object on the planet?

A 3.0 N
B 8.0 N
C 48 N
D 120 N

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6

An astronaut has a mass of 80 kg on Earth. He travels to the Moon where the gravitational field strength is smaller.

What happens to his mass and weight?

	mass	weight
A	decreases	decreases
B	unchanged	decreases
C	unchanged	unchanged
D	decreases	unchanged

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7

A rock has a weight of 24 N on a planet where gravitational field strength is 6.0 N/kg.

What is the mass of the rock?

A 0.25 kg
B 4.0 kg
C 18 kg
D 144 kg

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8

A student wants to measure the weight of a bag.

Which instrument should be used?

A electronic balance
B force meter
C measuring cylinder
D stopwatch

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9

A student wants to measure the mass of a block.

Which instrument should be used?

A force meter
B measuring cylinder
C electronic balance
D voltmeter

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10

Which quantity is a vector?

A density
B mass
C volume
D weight

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For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

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11

Which row correctly compares mass and weight?

	mass	weight
A	force	quantity of matter
B	measured in kg	measured in N
C	changes with planet	unchanged with planet
D	vector	scalar

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12

A beam balance is used to compare two objects.

What does the beam balance compare directly?

A densities
B masses
C volumes
D weights only

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13

A force meter reads 14.7 N when an object is hung from it. Take g = 9.8 N/kg.

What is the mass of the object?

A 0.67 kg
B 1.5 kg
C 4.9 kg
D 144 kg

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14

An object has mass 3.5 kg. On a planet, its weight is 21 N.

What is the gravitational field strength on the planet?

A 0.17 N/kg
B 6.0 N/kg
C 17.5 N/kg
D 73.5 N/kg

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15

A student writes: “An object with greater mass has greater inertia.”

What does this mean?

A It has a greater gravitational field strength.
B It has a greater resistance to change in motion.
C It has a greater volume.
D It has a greater density.

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16

Which object has the greatest inertia?

A 0.5 kg ball
B 2.0 kg brick
C 5.0 kg box
D 10 kg trolley

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17

An object is taken from Earth to a planet where g is twice as large.

What happens to its mass and weight?

	mass	weight
A	doubles	doubles
B	unchanged	doubles
C	halves	doubles
D	unchanged	halves

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18

A satellite moves farther away from Earth, where the gravitational field strength is smaller.

What happens to the satellite’s mass and weight?

A mass decreases, weight decreases
B mass unchanged, weight decreases
C mass unchanged, weight increases
D mass increases, weight unchanged

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19

Which equation defines gravitational field strength?

A g = m / W
B g = W / m
C g = W × m
D g = m − W

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20

An object has a mass of 0.60 kg and a weight of 9.0 N on a planet.

What is the gravitational field strength on the planet?

A 0.067 N/kg
B 5.4 N/kg
C 9.6 N/kg
D 15 N/kg

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21

Which statement describes a gravitational field?

A a region where a charge experiences a force
B a region where a mass experiences a force
C a region where current flows
D a region where pressure is constant

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22

A student measures the mass of a liquid. The empty beaker has mass 120 g. The beaker plus liquid has mass 315 g.

What is the mass of the liquid?

A 120 g
B 195 g
C 315 g
D 435 g

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23

A liquid has mass 160 g and volume 200 cm³.

What is its density?

A 0.80 g/cm³
B 1.25 g/cm³
C 40 g/cm³
D 32 000 g/cm³

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24

A metal block has mass 540 g and volume 60 cm³.

What is its density?

A 0.11 g/cm³
B 9.0 g/cm³
C 480 g/cm³
D 32 400 g/cm³

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25

A cube has side length 3.0 cm and mass 216 g.

What is its density?

A 8.0 g/cm³
B 24 g/cm³
C 72 g/cm³
D 648 g/cm³

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For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

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26

A rectangular block has dimensions 5.0 cm × 4.0 cm × 2.0 cm. Its mass is 320 g.

What is its density?

A 4.0 g/cm³
B 8.0 g/cm³
C 40 g/cm³
D 1600 g/cm³

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27

A solid has density 2.5 g/cm³ and volume 40 cm³.

What is its mass?

A 0.063 g
B 16 g
C 100 g
D 1600 g

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28

A liquid has density 0.90 g/cm³ and mass 180 g.

What is its volume?

A 0.0050 cm³
B 162 cm³
C 200 cm³
D 1800 cm³

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29

A material has density 7.8 g/cm³.

What is this density in kg/m³?

A 0.0078 kg/m³
B 7.8 kg/m³
C 780 kg/m³
D 7800 kg/m³

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30

A material has density 1200 kg/m³.

What is this density in g/cm³?

A 0.0012 g/cm³
B 1.2 g/cm³
C 12 g/cm³
D 120 g/cm³

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31

A stone is placed into a measuring cylinder. The water level rises from 36 cm³ to 51 cm³. The stone has mass 45 g.

What is the density of the stone?

A 0.33 g/cm³
B 0.80 g/cm³
C 3.0 g/cm³
D 15 g/cm³

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32

A metal object has mass 270 g. When placed in water, the water level rises from 80 cm³ to 110 cm³.

What is the density of the metal?

A 2.45 g/cm³
B 3.0 g/cm³
C 9.0 g/cm³
D 30 g/cm³

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33

A student wants to determine the density of an irregularly shaped stone which sinks in water.

Which apparatus is required?

A balance, measuring cylinder and water
B ruler, stopwatch and water
C thermometer, balance and ruler
D force meter and stopwatch

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34

A student wants to determine the density of a wooden block that floats in water.

Which method is most suitable?

A Use only the rise in water level when the block floats.
B Measure mass using a balance and volume from length × width × height.
C Measure weight using a stopwatch and divide by volume.
D Use a measuring cylinder only.

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35

A small metal cube has side length 2.0 cm and mass 72 g.

What is its density?

A 4.5 g/cm³
B 9.0 g/cm³
C 18 g/cm³
D 36 g/cm³

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36

A cube has density 5.0 g/cm³ and mass 625 g.

What is its volume?

A 0.0080 cm³
B 125 cm³
C 3125 cm³
D 125 000 cm³

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37

A block has density 4.0 g/cm³ and volume 25 cm³.

What is its mass?

A 0.16 g
B 6.25 g
C 100 g
D 625 g

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38

A liquid has density 1.2 g/cm³ and volume 75 cm³.

What is its mass?

A 0.016 g
B 62.5 g
C 90 g
D 900 g

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39

The mass of an empty measuring cylinder is 90 g. The mass of the measuring cylinder containing 50 cm³ of liquid is 130 g.

What is the density of the liquid?

A 0.40 g/cm³
B 0.80 g/cm³
C 2.6 g/cm³
D 4.4 g/cm³

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40

A student measures the density of a liquid.

Which readings are needed?

A mass of liquid and temperature of liquid
B mass of liquid and volume of liquid
C weight of liquid and time taken to pour it
D volume of liquid and depth of liquid

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For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

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41

A student measures the density of a regular solid cube.

Which readings are needed?

A mass and side length
B weight and time
C volume only
D temperature and mass only

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42

A cube of side 4.0 cm has density 2.0 g/cm³.

What is its mass?

A 8.0 g
B 32 g
C 64 g
D 128 g

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43

A cuboid has mass 240 g and dimensions 6.0 cm × 5.0 cm × 4.0 cm.

What is its density?

A 0.50 g/cm³
B 2.0 g/cm³
C 15 g/cm³
D 120 g/cm³

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44

A student measures the mass and volume of several pieces of the same material.

Which graph should be a straight line through the origin?

A mass against volume
B mass against temperature
C volume against time
D density against volume

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45

For a fixed material, mass is directly proportional to volume.

What does the gradient of a mass–volume graph represent?

A density
B gravitational field strength
C pressure
D weight

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46

For a fixed material, volume is plotted on the y-axis and mass on the x-axis.

What does the gradient represent?

A density
B 1 / density
C mass × volume
D gravitational field strength

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47

A graph of mass against volume for a material has gradient 2.7 g/cm³.

What is the density of the material?

A 0.37 g/cm³
B 2.7 g/cm³
C 27 g/cm³
D cannot be determined

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48

A graph of volume against mass for a material has gradient 0.20 cm³/g.

What is the density of the material?

A 0.20 g/cm³
B 5.0 g/cm³
C 20 g/cm³
D 50 g/cm³

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49

Two objects have the same volume. Object X has twice the mass of object Y.

Which statement is correct?

A X has half the density of Y.
B X has the same density as Y.
C X has twice the density of Y.
D X has four times the density of Y.

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50

Two objects have the same mass. Object P has twice the volume of object Q.

Which statement is correct?

A P has half the density of Q.
B P has the same density as Q.
C P has twice the density of Q.
D P has four times the density of Q.

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For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

Chapter 3 Answer Key

Q	Ans	Q	Ans	Q	Ans	Q	Ans	Q	Ans
1	C	11	B	21	B	31	C	41	A
2	C	12	B	22	B	32	C	42	D
3	C	13	B	23	A	33	A	43	B
4	B	14	B	24	B	34	B	44	A
5	C	15	B	25	A	35	B	45	A
6	B	16	D	26	B	36	B	46	B
7	B	17	B	27	C	37	C	47	B
8	B	18	B	28	C	38	C	48	B
9	C	19	B	29	D	39	B	49	C
10	D	20	D	30	B	40	B	50	A

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

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Detailed Explanations

1. C

• Mass is the quantity of matter in an object.

• It is measured in kg using a balance.

• A describes weight.

• B is wrong because a force meter measures weight/force.

• D is wrong because mass does not change when gravitational field strength changes.

2. C

• Weight is the gravitational force acting on an object.

• Weight = mass × gravitational field strength.

• Weight is measured in newtons, N.

• Weight is a vector because it acts towards the centre of the planet.

3. C

• Weight = mass × gravitational field strength

• W = mg

• W = 5.0 × 9.8

• W = 49 N

4. B

• g = W / m

• So m = W / g

• m = 196 / 9.8

• m = 20 kg

5. C

• W = mg

• W = 12 × 4.0

• W = 48 N

6. B

• Mass stays unchanged because the astronaut still has the same quantity of matter.

• Weight decreases because gravitational field strength is smaller on the Moon.

• So mass is unchanged, weight decreases.

7. B

• g = W / m

• So m = W / g

• m = 24 / 6.0

• m = 4.0 kg

8. B

• Weight is a force.

• Forces are measured using a force meter.

• Electronic balance measures mass, not weight.

9. C

• Mass is measured using an electronic balance.

• Force meter measures weight.

• Measuring cylinder measures volume.

• Voltmeter measures potential difference.

10. D

• Weight is a force.

• Force has magnitude and direction.

• Therefore weight is a vector.

• Mass, density and volume are scalars.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

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11. B

• Mass is measured in kg.

• Weight is measured in N.

• A is reversed.

• C is reversed because mass stays unchanged while weight changes with planet.

• D is wrong because mass is scalar and weight is vector.

12. B

• A beam balance compares masses.

• Technically it balances weights, but because both objects are in the same gravitational field, comparing their weights compares their masses.

• In exam language: beam balance/equal-arm balance compares mass.

13. B

• W = mg

• m = W / g

• m = 14.7 / 9.8

• m = 1.5 kg

14. B

• g = W / m

• g = 21 / 3.5

• g = 6.0 N/kg

15. B

• Inertia is resistance to change in motion.

• Greater mass means greater inertia.

• A heavier object is harder to start moving, stop, or change direction.

16. D

• Greater mass = greater inertia.

• The 10 kg trolley has the greatest mass.

• Therefore it has the greatest resistance to change in motion.

17. B

• Mass does not change from planet to planet.

• Weight = mg.

• If g becomes twice as large, weight doubles.

• So mass is unchanged and weight doubles.

18. B

• Moving farther from Earth reduces gravitational field strength.

• Mass stays unchanged.

• Weight decreases because W = mg and g decreases.

19. B

• Gravitational field strength = weight / mass.

• g = W / m

• Unit: N/kg.

• C is wrong because multiplying W and m does not define g.

20. D

• g = W / m

• g = 9.0 / 0.60

• g = 15 N/kg

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21. B

• A gravitational field is a region where a mass experiences a force.

• A is describing an electric field.

• C and D are unrelated.

22. B

• Mass of liquid = mass of beaker + liquid − mass of empty beaker

• Mass of liquid = 315 − 120

• Mass of liquid = 195 g

23. A

• Density = mass / volume

• Density = 160 / 200

• Density = 0.80 g/cm³

24. B

• Density = mass / volume

• Density = 540 / 60

• Density = 9.0 g/cm³

25. A

• Volume of cube = side³

• Volume = 3.0 × 3.0 × 3.0 = 27 cm³

• Density = 216 / 27

• Density = 8.0 g/cm³

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

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26. B

• Volume = length × width × height

• Volume = 5.0 × 4.0 × 2.0

• Volume = 40 cm³

• Density = 320 / 40

• Density = 8.0 g/cm³

27. C

• Density = mass / volume

• So mass = density × volume

• Mass = 2.5 × 40

• Mass = 100 g

28. C

• Density = mass / volume

• So volume = mass / density

• Volume = 180 / 0.90

• Volume = 200 cm³

29. D

• 1 g/cm³ = 1000 kg/m³

• 7.8 g/cm³ = 7.8 × 1000

• Density = 7800 kg/m³

• This conversion is a proper MCQ trap. Never multiply by 100 only.

30. B

• 1000 kg/m³ = 1 g/cm³

• 1200 kg/m³ = 1.2 g/cm³

• So answer = 1.2 g/cm³

31. C

• Volume of stone = final reading − initial reading

• Volume = 51 − 36 = 15 cm³

• Density = mass / volume

• Density = 45 / 15

• Density = 3.0 g/cm³

32. C

• Volume of metal = 110 − 80 = 30 cm³

• Density = 270 / 30

• Density = 9.0 g/cm³

33. A

• Density requires mass and volume.

• Mass is measured using a balance.

• Volume of irregular stone is found using a measuring cylinder and water.

• Therefore: balance, measuring cylinder and water.

34. B

• A wooden block floats, so displacement in water only gives the volume of the submerged part.

• Since it is a regular block, measure:

  • mass using balance

  • volume using length × width × height

• Then density = mass / volume.

35. B

• Volume of cube = 2.0 × 2.0 × 2.0

• Volume = 8.0 cm³

• Density = 72 / 8.0

• Density = 9.0 g/cm³

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36. B

• Density = mass / volume

• So volume = mass / density

• Volume = 625 / 5.0

• Volume = 125 cm³

37. C

• Mass = density × volume

• Mass = 4.0 × 25

• Mass = 100 g

38. C

• Mass = density × volume

• Mass = 1.2 × 75

• Mass = 90 g

39. B

• Mass of liquid = 130 − 90 = 40 g

• Volume = 50 cm³

• Density = 40 / 50

• Density = 0.80 g/cm³

40. B

• Density = mass / volume.

• Therefore the readings needed are:

  • mass of liquid

  • volume of liquid

• Temperature and depth are not needed for basic density calculation.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

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41. A

• For a regular solid cube:

  • measure mass using balance

  • measure side length using ruler

  • calculate volume = side³

  • calculate density = mass / volume

42. D

• Volume of cube = side³

• Volume = 4.0 × 4.0 × 4.0

• Volume = 64 cm³

• Mass = density × volume

• Mass = 2.0 × 64

• Mass = 128 g

43. B

• Volume = 6.0 × 5.0 × 4.0

• Volume = 120 cm³

• Density = 240 / 120

• Density = 2.0 g/cm³

44. A

• For the same material:

  • mass is directly proportional to volume

• So a graph of mass against volume is a straight line through the origin.

• The gradient gives density.

45. A

• On a mass–volume graph:

  • gradient = change in mass / change in volume

• Since density = mass / volume,

• gradient = density

46. B

• Here volume is on the y-axis and mass is on the x-axis.

• Gradient = volume / mass

• Density = mass / volume

• So gradient = 1 / density

• Sneaky graph trap. Cambridge enjoys this nonsense.

47. B

• For a mass against volume graph:

  • gradient = density

• Gradient = 2.7 g/cm³

• Density = 2.7 g/cm³

48. B

• For a volume against mass graph:

  • gradient = volume / mass

  • gradient = 1 / density

• Gradient = 0.20 cm³/g

• Density = 1 / 0.20

• Density = 5.0 g/cm³

49. C

• Density = mass / volume.

• Same volume, but X has twice the mass.

• Therefore X has twice the density of Y.

50. A

• Density = mass / volume.

• Same mass, but P has twice the volume of Q.

• Greater volume with same mass means lower density.

• P has half the density of Q.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

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Common Traps From This Chapter

Trap	Correct Rule
Confusing mass and weight	mass = matter, weight = gravitational force
Unit of mass	kg
Unit of weight	N
Instrument for mass	electronic balance / beam balance
Instrument for weight	force meter
Mass on Moon	unchanged
Weight on Moon	decreases
Formula for weight	W = mg
Formula for g	g = W / m
Meaning of inertia	resistance to change in motion
Density formula	density = mass / volume
Regular solid volume	length × width × height
Cube volume	side³
Irregular solid volume	final cylinder reading − initial reading
Floating object	displacement only gives submerged volume unless fully submerged
g/cm³ to kg/m³	multiply by 1000
kg/m³ to g/cm³	divide by 1000
Mass–volume graph gradient	density
Volume–mass graph gradient	1 / density
Same volume, larger mass	larger density
Same mass, larger volume	smaller density