Answer: Option B Similar questions https://www.sgphysicstuition.com/post/video-01-how-to-find-resultant-force-of-two-or-three-forces-without-drawing-vector-diagram https://www.sgphysicstuition.com/post/video-02-finding-resultant-force-from-vector-diagram-provided https://www.sgphysicstuition.com/post/finding-resultant-velocity-on-boat-or-plane-with-wind

Internal energy of a substance is the sum of kinetic energy and  potential energy of the molecules. kinetic energy  is directly proportional to the temperture of the substance potential energy  is related to the average spacing between the molecules (PE increases as spacing increases) - (for O-level, we can simplify it and treat it as PE will only change when there is a change of state . E.g during melting, the intermolecular forces are overcome and molcules are further now, hence PE increases. During melting, temp remains constant, hence KE remains the same) - i.e at any time, there is only either KE or PE change during the heating or cooling curve. As the substance is heated : energy is transferred into the internal store of the substance. internal energy increases . As the substance is cooled : energy is transferred out  of the internal store of the substance. internal energy decreases .

In the syllabus, we are required to understand the orders of magntiude of various objects. Though we may no need to memorise the exact values, the rough range and orders of magnitude of sizes are important. I will show some examples of the past years questions so have a better idea how to solve them. You can view the video for the explanation and sample questions with answers. Below are the sample questions from past years. 2024NAp1q2 Answer: Option A 2015SPp1q1 Answer: Option C 2016PPp1q1 Answer: Option C 2015PPp1q1 Answer: Option C 2019PPp1q7 2023PPp1q3 Answer: Option D

Instead of the usual vector diagram involving forces, these questions involve speed in a specific direction, which is velocity. Velocity is a vector quantity , which has both magnitude and direction . Hence we can apply the vector diagram (parallelogram method or tip-to-tail method) to these questions. These 3 questions are similar and the last one is a bit tricky. So do go through all. Question 01 Answer: Option B Question 02: 2012P1Q2 Answer: Option A Question 03: 2021PPp1Q1 Answer: Option C Similar type of questions: https://www.sgphysicstuition.com/post/video-01-how-to-find-resultant-force-of-two-or-three-forces-without-drawing-vector-diagram https://www.sgphysicstuition.com/post/video-02-finding-resultant-force-from-vector-diagram-provided

Finding the resistance of unknown resistor R

Flemeng's Left Hand Rule, using your left hand, with the thumb, 1st finger and 2nd finger all 90 degrees to one another. This is covered in Electromagnetism. 1. Thumb represents the Force (F) – the direction the conductor (like a wire) will move. 2. First Finger (index finger) represents the Magnetic Field (B) – the direction of the magnetic field, from North to South. 3. Second Finger (middle finger) represents the Current (I) – the direction of conventional current flow (from positive to negative). So, if you arrange your left hand with your thumb, first finger, and second finger perpendicular to each other: Point your First Finger in the direction of the magnetic field. Point your Second Finger in the direction of the current. Your Thumb will point in the direction of the force, showing the movement of the conductor. This rule is particularly helpful in predicting the direction of force in a DC motor, where a current-carrying conductor is placed in a magnetic field.

Fleming's Right-Hand Rule is another useful rule for understanding electromagnetic induction. This rule helps us determine the direction of induced current when a conductor (such as a wire) moves within a magnetic field. It’s commonly applied in generators. Here’s how it works: 1. Thumb represents the Motion (or Force) – the direction in which the conductor is moving. 2. First Finger (index finger) represents the Magnetic Field (B) – the direction of the magnetic field from North to South. 3. Second Finger (middle finger) represents the Induced Current (I) – the direction of the induced current. To use Fleming's Right-Hand Rule, hold out your right hand with your thumb, first finger, and second finger all perpendicular to each other: Point your First Finger in the direction of the magnetic field. Point your Thumb in the direction of the conductor's movement. Your Second Finger will point in the direction of the induced current. This rule is very useful in understanding how generators work. When a conductor moves through a magnetic field, it experiences a change in magnetic flux, which induces a current in the conductor – the direction of which can be predicted with this rule.

2002PPQ38, 2003PPQ38, 2005PPQ37, 2006PPQ38, 2007PPQ39 Answer: Option B Answer: Option D Answer: Option B Answer: Option C Answer: Option B Answer: Option A Answer: Option C Answer: Option B Answer: Option D