Have you gotten your TYS???
The Physics of Scuba Diving | WIRED
How many girls are there?
Am I paying a lot on electrical bill for charging my phone?
With new advances in mobile devices, the battery capacity of the lithium-ion battery increases with each new model.
For instance, the flagships phone like iPhone 14 max Pro has an capacity of 4323 mAh, Samsung S22 Ultra 4855 mAh and the Z fold 4 4400 mAh. We tend to think that the constant charging of our phones will use a lot electrical energy, hence increases our electrical bill.
But is it true?
Trash bag – energy transfer and inertia
Polar bear understands the concept of preasure
Which V I readings are for torch lamp?
Pure Physics 2019 P1Q33 and 2007P1Q28
Torch lamp or bulb is a non-ohmic conductor. The V-I graph has an increasing gradient indicating resistance increases. As the current through the filament of bulb increases, temperature increases and resistance increases.
For an ohmic conductor, the graph of V against I is a straight line with constant gradient and passes through the origin.
Something to thing about:
What if there is an option E where
V increases from 0, 1, 2, 3
I increases from 0, 6, 10, 12 respectively
The graph will be a typical ohmic graph, similar shape to option B, but will you choose E?
Refer to the 2nd part of the video from 3min 40s
Watch “How Dangerous is a Penny Dropped From a Skyscraper?” on YouTube
INERTIA – demo by a sport car
Direction of friction on the wheel
There have been a few questions in Olevel asking students the direction of the friction on the wheel, It is important to consider if the wheel is connected to the engine or not.
Below is an illustration on this concept.
You can view the explanation plus the 4 examples from Olevel p1 in the video below.
Examples
Refer to the video above for the answers
2013 PurePhysics P1Q30 – Direction of the electric field
Ans: Option A
View the video tutorial for the explanation:
2021 SciPhy P1Q15 Electric field lines between the two charges
View the video tutorial for the explanation
Isn’t tyre with tread better in providing grip/traction/friction on the road in all weather?
Most of us know that when the treads of our typical car tyres are worn out, we need to change as to provide grip, hence our car will not skid easily.
But actually, the treads of our typical car serve a more important role during rainy days. They allow the water to be displaced (quickly letting the water to move into the treads) so that the tyres can still maintain contact with the road to provide the grip. Of course, if you still go too fast on a wet road, that layer of water may not be able to be displaced in time, hence grip on the road is greatly reduced and the car is likely to skid.
Especially in the recent F1 race in Singapore, due to the wet weather, the cars had to changed to hard wet tyres. Many may be puzzled why F1 cars uses smooth slick tyres during dry weather, contrary to our common sense for our typical cars. The graphic below hopes to provide some basic explanation to the wet and dry tyre and the function of the tread on tyre. Hope it helps.
The following video gives a good overview of how a tyre works. There is a lot of science behind them.
Turning Effect of Forces – Moment – Basic Concepts
Once you know the basic concepts, try applying the POM in other application questions. Refer to the two videos below.
Application of refraction, total internal reflection and lens
Will it topple?
To indicate the weight, you have to draw the arrow from the CG vertically down.
Basic Concepts on Turning Effect of Forces (Moment)
Why evaporative cooler does not work well in Singapore?
The world’s whitest paint can cool your house — and the Earth
https://www.freethink.com/environment/whitest-white-paint
White surface is a good reflector of radiation and light. This paint is even better!!
General Wave Properties
How to mark 2 points (at a distance apart) at the same level? (water finds its own level)
The video below demonstrates that water will find its own level.
An olevel question requires this concept:
An apartment block receives water from a nearby reservoir. A pump is necessary to lift the water into a storage tank at the top of the building.
The gravitational field strength is 10 N / kg. How much energy does the pump supply to lift each kilogram of water into the tank?
Solutions: 100J
Water will always find its own level. Hence with or without the pump, the water level in the pipe in the building will be of the same level as the reservoir. Hence, the pump is only needed to pump water up a height of 10m only (instead of the 50m).
Energy, E = mgh = 1 kg x 10 N/kg x 10m = 100 J
Hand Boiler
Hand boiler toy is a demonstration of thermal transfer and how the 3 states of matter interact.
The coloured liquid inside is usually ethyl alcohol, which is a volatile liquid (i.e. a liquid with low boiling point). Similar to the alcohol swab you applied on hand during injection. Such liquid evaporates easily in room temperature or when heat is applied to it.
Thermal energy flows from a region of higher temperature to a region of lower temperature. When we hold the boiler in our hand, the thermal energy from our hand (body temp about 37oC) is transferred to the lower bulb of the boiler. The ethyl alcohol evaporates and also due to heated air above the liquid, the air expands and the pressure increases. The air pushes the liquid down, hence pushing the liquid up the shaft into the top bulb.
The bubbling of the liquid in the top bulb is not due to ‘boiling’ of the liquid. Rather, the gas in the lower bulb continues to expand and it goes to the top bulb, hence giving the illusion that the liquid is ‘boiling’.
Understanding Hydraulic System Overview
Understanding Hydraulic System 01
Understanding Hydraulic System + Lever 02
Direction of Frictional Force on Tyre or Wheel (updated)
For these type of questions, it is important to identify which tyre/wheel is connected/powered by the engine or the person.
On each tyre or wheel, there are actually two types of frictional force.
- Frictional force on wheel
- Frictional force on road/ground
Examples:
Oscillating or Vibrating Object in a Wave Motion
When an object is oscillating or vibrating in a wave motion, the speed of the object varies along the path.
In this video, there are 3 examples of vibrating object.
1) Mass vibrating vertically from a spring
2) Pendulum bob oscillating
3) A particle vibrating up and down on a transverse wave
In general, when the object is at the extreme ends of the oscillation or vibration, it is momentarily at rest. Hence its KE at these points is minimum or 0 J.
And in the middle that is where the object is travelling the fastest, hence the KE is the maximum.
Determine the motion of the particles on transverse wave
Instead of imaging how the particles will move and guess their motion, there is a technique which can help you to determine that.
In addition, when particles are in phase, it means that both particles on the wave have the same velocity and same displacement. It means both have the same speed in the same direction and same distance and direction away from the rest position.
Particles that are out of phase means both are having the same speed but in opposite direction.
Refer to the video below to find out more.
Question 01: 2005/2008 PP P1 Q20/Q18
Question 02: 2018 PP P1 Q24
Revision on Kinematics
Video 01: The various physical quantities in kinematics
Video 02: Acceleration
Video 03: Graphical Analysis of Motion (Displacement (distance)-Time Graph and Velocity (speed)-Time Graph)
Video 04: Describing the motion of the car – practice
Video 05: Free-fall, acceleration due to gravity
Video 06: Motion of 2 objects
Understanding Conservation of Energy and applying in calculation questions
Drawing the best fit line or curve
Graphs of Transverse Wave – E.g. Water waves
Refer to the Graphs of Sound Waves here
Barometer with a layer of water – Find height of mercury H
Diodes and bulbs, which bulbs is lighted up when switch S is open and closed
PP2017p1q21 Sound – time taken for the next rarefaction to arrive at the point P
DC Question – Find unknown R, given the voltmeter readings when switch P and Q are closed respectively
Answer: Option A
Temperature – Thermocouple – Find the unknown temperature
Answer: 800 oC
Determine focal length of lens using mirror with object and image aligned
Click on the link below to view another similar question.
Lens – screen and mirror – what kind of image formed on screen
Distance of sound detector from walls
Answer: Option B
Tidal wave energy
Understanding cathode-ray oscilloscope CRO
Conservation of energy on the complete driver golf swing
Slinky coil guru!
Slinky coil can be used to show transverse or longitudinal wave. But do not quote slinky coil as an example of either wave.
But this guy is really pro with a slinky coil!!
Minimum distance h mirror from the floor
Answer: B
Maybe I have been teaching wrongly…..
The skin of the orange has pockets of air. This makes the overall density of the orange lower than water, hence the whole orange can float. Without the skin, the ‘naked’ orange is denser than water hence it sinks.
But maybe we should include the feeling of the ‘naked’ orange 🙂 😀 hahaha
Do your TYS!
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