Table of Contents
Definitions, Theories, Formulas for IGCSE Physics 1.3
When it comes to this subtopic, there are a few definitions, theories and formulas to remember,
Definitions and theories
- Mass: The measure of the quantity of matter relative to the observer. It does not change no matter what.
- Weight: It is the gravitational force of an object with mass. It changes depending on the gravitational force acting on the object.
- Density: According to its formula, it means the mass per volume of an object. It is directly proportional to mass and indirectly proportional to volume.
- Floating: An object with lower density than the fluid it is placed in will float, while an object with higher density than the fluid it is placed in will sink. It also depends on upthrust. If the upthrust of an object is greater than or equal to its weight, it will float, if not, it will sink.
Formulas
- Mass: There is no formula for mass because it is a fundamental quantity, but it is usually measured in kilograms(kg) or grams(g).
- Weight: Mass x Acceleration due to gravity (W = mg; g is a constant of 9.8 m/s^2)
- Density: mass / volume (p = m/V)
Alright, now, let’s immediately get on with the questions.
IGCSE PHYSICS 1.3 OPEN ENDED EXAM QUESTIONS
1.3.1 A student wishes to find the volume of a piece of wood of irregular shape. Her experiment requires the use of a small brass object of mass 200 g.
Calculate the volume of the brass object. The density of brass is 8.4 g / cm3
In this question, we are asked to find the volume of the brass object. We are also given the density and mass of the brass object. So, all we have to do is use a formula that relates mass, volume, and density which is “density = mass / volume (p = m/V)”. The next thing we need to look at are the units of measurement.
In this case, the units are both equal to each other in grams, so there will be no need for conversion. We also know from the unit of density, that the final answer will be in cm^3. All we have to do is remodel the formula so that V is the subject, making it, “V = m/p”. Substitute the values that we are given, V = 200 / 8.4, and we get V = 23.81 cm^3, round it off to two significant figures, and we get the final answer of 24 cm^3.
1.3.2 A student has 500 identical, rectangular sheets of paper. The mass of 1.0 m^2 of the paper is 0.080 kg.
Using a meter rule, she measures the length of one sheet of paper and its width. The length is 0.300 m and the width is 0.210 m.
Calculate the mass of one sheet of paper.
In this question, we have a few numbers that we have to consider. First we need to find a value that can be compared with 1.0m^2 of paper. It is given that one sheet of paper is 0.300m by 0.210m, which means that we can find the area of the paper by multiplying these two values, giving us 0.063m^2. Now that we have this value, we know that 1.0m^2 of the paper is 0.080kg, so we can find the mass of one sheet of paper by simply dividing 0.063 by 1 and then multiplying that by 0.080. This gives us 0.00504kg per sheet of paper.
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For now, there’s not that many questions that can be made from just IGCSE Physics 1.3. In fact, this knowledge will be used more when dealing with pressure, energy, and other topics. So for now, just know the main formulas and next I will talk to you guys about Forces.
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