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A-Level Physics Tuition Singapore/H2 Physics Tuition/JC Physics Tutor

Hi A-level/H2/JC Physics Tuition students

Mastering Qualitative Questions

Chapter 8: Gravitational Part 1

1. As the satellite orbits the Earth, it gradually loses energy because of air resistance. State and explain the effect of this change on the radius of the orbit and the speed of the satellite. [2]

2. Explain what is meant by a geostationary satellite. State the conditions that must be satisfied by the satellite before it can be considered as geostationary. [2]

3. The man is standing on a weighing scale. He finds that his weight shown on the scale is different at the equator and at the North pole. Explain why there is a difference. [2]

4. The Moon is constantly attracted towards the Earth by gravitational attraction. Explain why it does not fall into the Earth. [2]

5. Explain why the geostationary satellite must be above the equator? [1]

6. Explain why acceleration of free fall at the equator is smaller than the acceleration of free fall at the pole? [1]

7. When 2 planets revolve around a common centre, what do they have in common? [1]

8. Under the heading Data, there is an entry
Acceleration of free fall g = 9.81 m s – 2
Compare and comment on small differences between this value, the value you obtained by using the concept gravitational force is the net force on the object and the value of 9.79 m s – 2 (which is the value obtained by making accurate measurements near the equator) [3]

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O-Level Additional Mathematics Tuition Singapore

Quadratic Equation

ax^2 + bx + c = 0

Sum of the roots = – (b/a)

Product of roots = (c/a)

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O Level E Maths Tuition Singapore/Tuition O Level E Maths/Tutor

Fraction

1. Proper fractions
The numerator is smaller than the denominator
Example 3/4 and 6/7

2. Improper fractions
The numerator is larger than the denominator
Example 5/4 and 9/7

3. Mixed Numbers
Numbers contains a whole number and a fractional part
Example 1 and 1/2

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O-Level Singapore/O-Level/Physics and Chemistry Tuition/Physics Tutor

Important Definitions – Alkanes & Alkenes

1. Saturated hydrocarbon are compounds containing only carbon and hydrogen and having single bonds between carbon atoms.

2. Unsaturated hydrocarbon are compounds containing only carbon and hydrogen and having double bonds between carbon atoms.

3. Alkane series has a general formula CnH2n+2

4. Alkenes series has a general formula CnH2n

5. Structural formula is the chemical formula that shows how the atoms are joined together in a molecue.

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O Level Chemistry Tuition Singapore/Chemistry O Level Tuition/Tutor

Important Definitions – Alkanes & Alkenes

1. Saturated hydrocarbon are compounds containing only carbon and hydrogen and having single bonds between carbon atoms.

2. Unsaturated hydrocarbon are compounds containing only carbon and hydrogen and having double bonds between carbon atoms.

3. Alkane series has a general formula CnH2n+2

4. Alkenes series has a general formula CnH2n

5. Structural formula is the chemical formula that shows how the atoms are joined together in a molecue.

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O-Level Singapore/O-Level/Physics and Chemistry Tuition/Physics Tutor

Key Points – Practical Electricity Part 2

6. Fossil fuels and nuclear energy are non-renewable energy sources. Solar energy, wind energy and hydroelectric generation are renewable energy sources.

7. Generally, non-renewable energy source produce electricity cheaper than
renewable energy.

8. A short circuit causes excessive current to pass through the circuit and produce a large amount of heat within a Short period of time.

9. Electricity can be dangerous due to
– damaged insulation which can cause electric shocks
– overheating of cables which can cause fire.
– damp conditions which can cause electric shocks.

10. Live wire carry current into homes while neutral wires carry current out of homes. Earth wires are connected to the ground for safety purposes.

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O-Level Singapore/O-Level/Pure Physics Tuition/Physics Tutor

Key Points – Practical Electricity Part 2

6. Fossil fuels and nuclear energy are non-renewable energy sources. Solar energy, wind energy and hydroelectric generation are renewable energy sources.

7. Generally, non-renewable energy source produce electricity cheaper than
renewable energy.

8. A short circuit causes excessive current to pass through the circuit and produce a large amount of heat within a Short period of time.

9. Electricity can be dangerous due to
– damaged insulation which can cause electric shocks
– overheating of cables which can cause fire.
– damp conditions which can cause electric shocks.

10. Live wire carry current into homes while neutral wires carry current out of homes. Earth wires are connected to the ground for safety purposes.

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A-Level Biology Tuition Singapore/H2 Biology Tuition/JC Biology Tutor

TOPIC 1: CELLULAR FUNCTIONS – Part 5

LEARNING OUTCOME

(e)Describe the structure of an amino acid and the formation and breakage of a peptide bond.

ESSAY ANSWER

Structure of amino acid
Amino acids comprise of a central carbon atom (alpha carbon) to which are
attached an amine group, a carboxylic acid group, a hydrogen group and a
variable R-group. The R-group may be polar, non-polar or charged. Charged
R-groups may be acidic (negatively charged) or basic (positively charged).

Peptide bond formation
A peptide bond is formed when a condensation reaction occurs between a
hydroxyl group from the carboxylic acid group of one amino acid, and a
hydrogen atom from the amine group from another amino acid. One water
molecule will be lost in this reaction.

Peptide bond breakage
The peptide bond is broken through a hydrolysis reaction. One water
molecule is used up for this reaction. This restores the hydroxyl group at the carboxylic acid group of one amino acid, and the hydrogen atom at the
amine group of the other amino acid.

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A-Level Economics Tuition Singapore/H2/H1 Economics Tuition

Hi H2/H1 Economics Tuition Students

Essay Question

2010 marked a trying time for the airline business. The eruption of the Icelandic volcano caused cancellations of 95,000 flights over Europe. One week later, the BP oil well exploded in the Gulf of Mexico, resulting in the worst oil spill in US history.
Using economic analysis, discuss the likely impact of the above events on the airline industry and related markets. [25]

Introduction
• Explain how market equilibrium price and quantity is achieved: via the intersection of the demand and supply curves.
• Identify that supply of airline travel has fallen due to cancellations of flights in Europe and the oil spill which led to an increase in costs of production.
• Identify that the demand for airline services over Europe would be affected due to the volcano eruption which has caused fear of flying (effect on demand depending on whether it is for holiday or business as tourists may choose to switch to other destinations or travel by other modes of transport but a businessman may need to travel by air for work)
• The related markets in this suggested answer would look at the market for a complementary good like the hotel industry and a substitute like rail travel.

Market for the airline industry
• Overall demand for air travel is expected to fall due to Icelandic volcano eruption (fear of flying). Demand for travel by holiday makers may fall but demand for business travel may not be affected by the fear of flying)  leftward shift of the demand curve
• Demand for air travel tends to be price elastic due to the presence of substitutes like rail travel, land travel like long haul buses and cars.
• The price elasticity of demand measures the degree of responsiveness of the quantity demanded of a good to a change in its price, ceteris paribus
• Illustrate how a leftward shift of the supply curve from S0 to S1 due to an increase in COP will have different effects on price and quantity, given different PED value.
• With reference to Figure 1, the demand curve D1 is relatively more price inelastic than demand curve D0. Given a leftward shift of the supply curve from S0 to S1, the more price inelastic the demand, the greater the effect on its price. As seen from Fig 1, for D1 the fall in quantity (demanded) Q1 is less than proportionate to a rise in its price, ceteris paribus.

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A Level GP/General Paper Tuition Singapore

Model Essay

Consider the view that advertising manipulates rather than informs.
In the modern society, advertisements take the centre stage in shaping our lives; advertisements give us knowledge about the way a product can help to build our individual identity into a unique construct one seeks to become. Yet, there is now growing doubt as to whether advertisements aim to inform the individual to help him or her shape their identity, or if it is the other way around – advertisements taking advantage of consumers’ tastes and using the information to manipulate innocent unknowing consumers. While advertisements do contain useful information, this information could at times be deceiving, often focussing on one primary aspect and leaving out the negative aspects. In fact, advertisements have increasingly become bolder in carrying out empty promises, hence giving the consumer false information. Therefore while advertisements do inform, the emerging trend is that this information is becoming less trustworthy, all the for the aim of misleading and manipulating the consumer, so as to generate wealth for the firm itself.

Advertisements have traditionally benefitted the individual, from providing the basic information on the use of the product to the benefit it brings, to who would be most suited to use the product, and the list goes on. To the busy urban commuter on a bus, the advertisement that wraps around almost the entire body of the bus can be seen as an efficient way to receive an update on the latest gizmos that could benefit him or her. After all, in the modern society each precious minute of time represents an opportunity cost and hence advertisements too become a key source of information that is useful in making decisions. One key aspect of advertisement is its ability to inform the consumer in a concise and distinct manner. Advertisements for brands such as Kit Kat spell out the benefit of their product not by producing scientific studies on how chocolates stimulate the growth of endorphins in the human body and hence uplift our moods; rather it features visual images of people from all walks of life in joy and laughter after eating a Kit Kat. Hence this succinctly gets the message through in not only the most efficient way but also the most persuasive manner. This the ability for the many tools that advertisements employ, be it appealing logos, visuals, sounds, provide the urban consumer with one primary benefit – getting the main crux of the benefit of the product in a short, sweet and simple manner. This makes advertisements one of the most accessible sources of information in the life of the busy, urban individual. Thus it seems the responsibility ultimately falls on the consumer to make a choice amongst the myriad of advertisements that he would surely chance upon daily because advertisements can only directly inform but cannot directly force the consumer to act or behave in the way that benefits the forms as the final choice lies in the hands of the consumer himself.

However, the growing pervasiveness of advertisements in the modern individual’s life could possibly have the counter effect of manipulating consumer behaviour rather than carrying out its role in laying out the possible options for the consumers. Increasingly, advertisements look not to provide a holistic and balanced assessment of a product to a consumer but rather, to use advertisement as a tool to appeal to the tastes of the consumer, such that in feeling the need to be true to his identity, the less savvy consumer is fooled into thinking that the product is being advertised is a necessity for him or her. In this way, advertisements cross from the boundary of laying out plain facts to help improve consumer knowledge and hence make better choices, to manipulating the consumers’ behavioural patterns. Increasingly, advertisers have employed a talent pool of psychologists to predict the reactions that consumers would have towards different forms of advertisements and hence shape their advertisement around that magic formula that would generate the best results for its product sales. One key area is in the use of the knowledge that sex sells. Iconic brands that have seen long-lasting results and have managed to survive despite the stiff market competition often employ advertisements that provoke and creates a long-lasting impression on the viewer. One such example is brands like Gucci perfumes that primarily market its scents that attract the opposite sex. In particular the Gucci Guilty scent features an advertisement with what appears to the viewer as two barely-clothed models wrapping around each other in a seductive manner. Hence the advertisers appeals to the modern woman who wishes to be attractive, and attempts to evoke the belief that in order to appeal to the opposite sex, the Gucci Guilty scent has the miraculous effect of doing so. In such advertisements, the information that the advertisement brings becomes greatly distorted. Since there is no concrete scientific evidence of such an effect, it becomes a deceptive tool that encroaches upon the individual’s belief system – that to be sexy and attractive, she has to first smell good. Thus advertisements can and are increasingly headed towards the goal of shaping consumers’ mindsets and even their fundamental belief systems so as to shape their purchasing behaviour.

Furthermore, advertisements are manipulative in the way it chooses to emphasise some of the products and conceal others, thus making it an untrustworthy source of information. For firms, this would mean that it would do anything in its power to maximise profits. Hence the question was never about how best to inform the consumer but rather how best to manipulate a consumer into buying a product. Hence, firms such as Starbucks play a clever game by highlighting a particular aspect of its product while leaving out the rest. In this case, Starbucks appeals to the fact that its coffee beans are obtained under Fairtrade and part of it goes to charity, it also hopes to convince the consumer into buying into the idea that by buying a cup of Starbucks coffee, he or she is also rewarded with the sense of satisfaction that he is benefitting society and thus belongs to the ‘wonderful” group of Starbucks-drinking group who are environmentally conscious. Yet, firms like Starbucks are deceptive in that they do not reveal that by paying such a high premium for the cup of Starbucks coffee, one would already have essentially paid the cost of the proceeds to charity and to the Fairtrade coffee source. Hence, in actuality, it was not the cup of Starbucks coffee that resulted in positive benefits for the society but rather the higher costs that the individual chose to pay for feeling that he is doing something good while drinking the coffee. In this way, advertisements are increasingly gaining an identity-based categorisation. Certain advertisements are directed at the cool-seeking crowd while others are aimed at the environmentally-conscious. Thus the side effect of this is that in focussing or creating a brand identity, the value of the information on the facts of the product the consumer gets becomes of secondary importance.

Advertisements have traditionally been a convenient source of information but it is also taking a changing profile – one that focuses more on manipulating the consumer rather than just merely giving information.

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A-Level Chemistry Tuition Singapore/H2 Chemistry Tuition/JC Chemistry Tutor

1. Concept: Redox Half Equations

(a) Define the term disproportionation. [1]

2. (Time allocation: 12 min)
(a) Mixtures of CaCl2 and NaCl are used for salting roads to prevent ice formation. 1.95 g sample of such mixture was dissolved in water and excess aqueous Na2C2O4 was added to completely precipitate the Ca2+ ions as CaC2O4.

The CaC2O4 formed was separated from the solution and dissolved in sulphuric acid. The resulting H2C2O4 solution was titrated with 37.8 cm3 of 0.102 mol dm-3 KMnO4 solution.

(i) Given that C2O42- is oxidized to form carbon dioxide, write a balanced equation for the reaction of C2O42- and MnO4-. [1]

(ii) Calculate the number of moles of H2C2O4 reacted with KMnO4. [1]

(iii) Calculate the mass of CaCl2 in the original sample. [2]

(iv) Hence, calculate the percentage mass of NaCl in the original sample.
[2]

(b) 20.0 cm3 of 0.100 mol dm-3 vanadium (II) solution, V2+(aq), reacted with 40.0 cm3 of a 0.100 mol dm-3 iron (III) solution. Iron (III) ions was reduced to form iron (II) ions in the reaction. Calculate the final oxidation state of vanadium in the above reaction. [2]

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A-Level Mathematics Tuition Singapore/JC Maths/H2 Math Tuition and Tutor

Hi A-Level/H2 Math Students

Arithmetic Progression

Definition

An arithmetic progression (A.P.) is a sequence of numbers in which each term other than the first term is obtained from the preceding one by the addition of a constant number called the common difference.

Therefore, if we let a be the first term and d be the common
difference of the sequence, then the sequence is an A.P. of the form

a, a + d, a + 2d, a + 3d, ……

general nth term = Un = a + ( n – 1)d

Sum of AP

Sn = (n/2)[2a+(n-1)d]

Sn = (n/2){First term + last term)

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A-Level Physics Tuition Singapore/H2 Physics Tuition/JC Physics Tutor

Hi A-level/H2/JC Physics Tuition students

Mastering Qualitative Questions

Chapter 7: Circular Motion

1. Using a rope, a bucket of water is swung in a vertical circle of radius 0.950 m.
The mass of the water and bucket is 3.25 kg. At the top of the circle, the speed of the bucket is 3.23 ms-1 and the bucket is upside down at this instant.
Explain qualitatively why the water in the bucket does not fall out. [2]

2. A small marble is projected from the ground at an initial speed of 2.5 m s – 1 at an angle of 53° above the horizontal. The same marble now slides at a speed of 2.5 m s – 1 along a horizontal surface towards a circular hump. State 2 differences between the circular motion performed by the marble as it slides over the hump and the projectile motion. [2}

3. A stone is attached to a string. The stone rotates in a circle of radius 79 cm, with its centre at C, at constant speed in a vertical plane,
Suggest why, in practice, it would be difficult to maintain a constant angular speed of the stone. [2]

4. A string may snap if it is attached to an object and the object is spun around a vertical pole. Suggest an explanation for this. [2]

5. The rider now makes the same left turn on a rough surface banked at 20o to the horizontal.
Assuming that the frictional forces remain as 70 N, and radius of curvature is still 60 m,
(a) Explain how the banked surface assists the rider in travelling around the corner at a higher speed. [1]
(b) Given that the cyclist now travels at a faster speed, state and explain whether it will move up or down the road. [2]

6 Use Newton’s laws of motion to explain why an object moving with uniform speed in a circle must experiences a force towards the centre of the circle. [2]

7 An object, when travelling at a constant speed in a circular motion, is said to have a centripetal acceleration. Explain why there is acceleration although the speed is constant. [2]

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O-Level Additional Mathematics Tuition Singapore

Solving Exponential Equations

In solving exponential equations, it is common to use one or both of the following methods:

Method 1
Expressing both sides in the same base, then equating the indices.

Method 2
Substitution

Example
2^x = 32
2^x = 2^5
Therefore x = 5

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