Curriculum
- 17 Sections
- 105 Lessons
- 365 Days
- 1. Measurement and Unitssome information5
- 2. Mass, Weight, & Density6
- 3. Motion5
- 4. Effect of Forces8
- 5 Moments & Momentum7
- 6. Energy, Work, Power & Pressure11
- 7. Kinetic Particle Model of Matter | Thermal physics5
- 8. Thermal Properties & Temperature | Thermal Physics5
- 9. Transfer of Thermal Energy | Thermal Physics5
- 10 Properties of Waves | Waves10
- 11. Light | Waves11
- 11.011.1 Reflection of Light
- 11.111.2 Investigating Reflection
- 11.211.3 Image Formation
- 11.311.4 Refraction of Light
- 11.411.5 Refractive Index | Snell’s Law
- 11.511.6 Total Internal Reflection
- 11.611.7 Thin Lenses & Ray Diagram
- 11.711.8 Diverging Lens
- 11.811.9 Short and Long Sightedness
- 11.911.10 Dispersion of Light
- 11.10Quiz – Light13 Questions
- 12. Electromagnetic Spectrum | Waves4
- 12. Electricity & Magnetism5
- 13. Electrical Quantities | Electricity11
- 14.013.1 Electrical Quantities
- 14.113.2 Electrical Conductors and Insulators
- 14.213.3 Electric Field
- 14.313.4 Electric Current
- 14.413.5 Direct Current and Alternating Current
- 14.513.6 Electromotive Force and Potential Difference
- 14.613.7 Resistance
- 14.713.8 Current Voltage Graphs
- 14.813.9 Electrical Resistance
- 14.913.10 Electrical Energy and Electrical Power
- 14.10Quiz 13 – Electrical Quantities21 Questions
- 14. Electrical Circuits7
- 15. Electromagnetic Effects14
- 16.015.1 – Electromagnetic Induction
- 16.115.2 Len’z Law
- 16.215.3 Electromagnetic Effects4 Questions
- 16.315.4 The A.C Generator
- 16.415.5 Quiz – The A.C Generator2 Questions
- 16.515.6 The D.C Motor
- 16.615.7 The D.C Motor3 Questions
- 16.715.8 Magnetic Effect of a Current
- 16.815.9 Magnetic Field Patterns Experiment
- 16.915.10 Magnetic Effect of a Current3 Questions
- 16.1015.11 Force on a current-carrying conductor
- 16.1115.12 Force on a current-carrying conductor2 Questions
- 16.1215.13 – The transformer
- 16.1315.14 – The transformer6 Questions
- 5. Nuclear Physics10
2.1 Mass and weight
Chapter 1 | Motion, Forces and Energy
2.1.1 Mass and weight
Mass
Mass is the measure of an object’s amount of matter, unaffected by its physical state (solid, liquid, or gas).
Unit: The unit of mass is kg.
Mass indicate two primary effects:
- Resistance to Change in Motion:
- Mass resists changes in motion.
- Greater mass results in increased resistance to acceleration or deceleration.
- Gravitational Attraction:
- All objects experience gravitational attraction towards the Earth.
- Greater mass leads to a stronger gravitational pull from the Earth.
Mass is a quantitative measure of a body’s inertia, representing its ability to maintain a state of rest or motion. It is a scalar quantity, measured in kilograms (kg) as the standard unit. The relationship between kilograms and grams is expressed as 1 kg = 1000 g.
❓ Exam Questions
1524/22-j21
Three students are asked what they understand by the term mass.
Their answers are listed.
1 Mass is the property of an object that resists a change in motion.
2 Mass is the quantity of matter an object contains.
3 Mass is the effect of a gravitational field on an object.
Which students are correct?
m =\( \frac{W}{ g}\) = \( \frac{2350}{ 9.8}\)
=240kg
Exam Tips
1. Mass and weight
- Be able to define and explain the difference between mass and weight. This is a common question on IGCSE physics exams.
- Understand that mass is a constant, while weight can change depending on the strength of the gravitational field. For example, an object would have less weight on the Moon than on Earth.
- Know the units of mass and weight. Mass is typically measured in kilograms (kg) or grams (g), while weight is measured in newtons (N).
2. Comparison of mass and weight
Here is a table comparing mass and weight:
Property | Mass | Weight |
---|---|---|
Definition | Measure of the amount of matter in an object | Force acting on an object due to gravity |
Quantity | Scalar | Vector |
Units | kg or g | N |
Constant | Yes | No, can change depending on the strength of the gravitational field |
- Be able to compare and contrast mass and weight. This is another common question on IGCSE physics exams.
- Understand the relationship between mass, weight, and gravitational field strength. This relationship is described by the equation
W = mg
, whereW
is weight,m
is mass, andg
is gravitational field strength. - Be able to solve problems involving mass, weight, and gravitational field strength. For example, you may be asked to calculate the weight of an object on a different planet, or the mass of an object given its weight and the gravitational field strength.
Summary
- The mass of an object is defined as the amount of matter in the object and it is the property on object that resists change in motion.
- The weight of an object is the force pulling the object downward.
- Weight of an object depends on mass and acceleration due to gravity.
- Weights ( and hence masses ) can be compared with balance.
- Mass is measured in kilograms while weight measured in newtons.
- Same objects are located at different planets have same masses but different weights because the gravitational field strength on both planets will be different.
Definitions
- Mass: The property of an object that resists any change in motion.
- Weight: The weight of an object on the Earth is defined as the force acting on the object by the Earth’s gravity. It is equal to the product of mass of an object and gravitational field strength at its location.
- Balance: The apparatus that is used to compare different weights to demonstrate that which weight is larger.
❓ Exam Question
1524/22-j21-2021-Q4
Two objects, X and Y, are suspended from identical springs. The extension in both springs is the
same.
What does this show about the masses and about the weights of objects X and Y?
0625/0972/22-Feb-Mar-2020-Q4
Diagram 1 shows a piece of flexible material that contains many pockets of air. Diagram 2 shows the same piece of flexible material after it has been compressed so that its volume decreases.
What happens to the mass and to the weight of the flexible material when it is compressed?
Example 1: What is the weight of an object sitting on the Earth surface if the mass of the object is 32kg?
Solution:
m = 32kg
By using W = m × g ,
W = 32 × 9.8 = 313.6N
Example 2: What is the mass of an object whose weight sitting on the Earth is 2350N?
Solution:
W=2350N
By using W=m× g, and
m =\( \frac{W}{ g}\) = \( \frac{2350}{ 9.8}\)
=240kg
Exam Tips
1. Mass and weight
- Be able to define and explain the difference between mass and weight. This is a common question on IGCSE physics exams.
- Understand that mass is a constant, while weight can change depending on the strength of the gravitational field. For example, an object would have less weight on the Moon than on Earth.
- Know the units of mass and weight. Mass is typically measured in kilograms (kg) or grams (g), while weight is measured in newtons (N).
2. Comparison of mass and weight
Here is a table comparing mass and weight:
Property | Mass | Weight |
---|---|---|
Definition | Measure of the amount of matter in an object | Force acting on an object due to gravity |
Quantity | Scalar | Vector |
Units | kg or g | N |
Constant | Yes | No, can change depending on the strength of the gravitational field |
- Be able to compare and contrast mass and weight. This is another common question on IGCSE physics exams.
- Understand the relationship between mass, weight, and gravitational field strength. This relationship is described by the equation
W = mg
, whereW
is weight,m
is mass, andg
is gravitational field strength. - Be able to solve problems involving mass, weight, and gravitational field strength. For example, you may be asked to calculate the weight of an object on a different planet, or the mass of an object given its weight and the gravitational field strength.
Summary
- The mass of an object is defined as the amount of matter in the object and it is the property on object that resists change in motion.
- The weight of an object is the force pulling the object downward.
- Weight of an object depends on mass and acceleration due to gravity.
- Weights ( and hence masses ) can be compared with balance.
- Mass is measured in kilograms while weight measured in newtons.
- Same objects are located at different planets have same masses but different weights because the gravitational field strength on both planets will be different.
Definitions
- Mass: The property of an object that resists any change in motion.
- Weight: The weight of an object on the Earth is defined as the force acting on the object by the Earth’s gravity. It is equal to the product of mass of an object and gravitational field strength at its location.
- Balance: The apparatus that is used to compare different weights to demonstrate that which weight is larger.