Refer to the video below to understand how to sketch the graph. For O-Level, we just need to focus on the general shape. 2024PP Paper 2 Q1 Related video https://youtu.be/IyCRlUv4A4A https://youtu.be/clD1b1i7yX0 https://youtu.be/en2RM_Z14AU https://youtu.be/JuK9pHHa-kk

For such questions, it is useful to understand conservation of energy. Work done by the pushing force = GPE + KE + work done against friction Answer: (a) 8.0J (b) 200 J (c) 464 J (d) 0.18 m/s2

Answer: Option A

Liquid pressure P = pgh P is pressure in pascal (Pa) p is the density of the liquid (kg/m3) g is gravitational field strength (10 N/kg) h is the height of the liquid (m) Answer: Option B Refer to the video explanation

C is the heat capacity of a body. It is the amount of internal energy transferred to a body per unit change in temperature. (Or for 1 degree Celcius change in temperature). SI unit : J/oC c is the specific heat capacity of a material. It is the amount of internal energy transferred to a unit mass of the material per unit change in temperature. SI unit: J/kg.oC The relationship between C and c is: C = mc where m is the mass of the substance Answer: Option C

Answer: Option D Note that the reading shown on the detector (536 counts per second) includes the sum of count rate from the radioactivity material and also the background radiation of 44 counts per second. So to find the count rate purely from the radioactive material, you need to first minus 44 from the 536 = 492 counts per second. Given that the half-life is 34 hrs, so in the duration of 68 hrs, there are 68/34 = 2 half-lives. So 492 c/s after 1 half-life will becomes 492/2 =246 c/s Another half-life later, it will becomes 246/2 =123 c/s Note that 123 c/s is purely from the radioactive material, not the reading on the detector. Hence to find the reading on the detector, you need to add back the background count of 44 c/s = 123 + 44 = 167 c/s

Answer: Option B Using conservation of energy (COE), the total energy of the car at X = total energy at Y. At X, the car only has gravitational potential energy. If there is no friction, the magnitude of the kinetic energy must be equal to the GPE at X. But since there is frictional force, there will be some energy wasted as work done against friction, usually in the form of internal (thermal) energy and sound energy. Hence, GPE at X = KE at Y + WD against friction Refer to the video explanation

Answer: Option B We usually encounter decay graph of the unstable radiaoactive substance. But this graph is the mass-time graph of the stable isotope. So the mass increases as time goes by.

Answer: Option D We always use FLHR to find the force on the wire. But magnetic forces is a action-reaction pair. So when the force acting on the wire is upwards, there is also an equal and opposite force acting downward on the magnet.

Answer: Option B LDR (light dependent resistor) is a type of input transducer. When light intensity decreases, the resistance of LDR increases and vice versa. You can redraw the circuit so that it looks like the usual potential divider that you are familiar with. Refer to the video below.

Answer: Option C This is a heating curve. So the specific latent heat of fusion here refers to the melting process, which occurs from time 100s to 250s.

Answer: Option A The direction of the magnetic field is downwards in the diagram. You can think of a North Pole of a magnet that is at the top and/or a South Pole at the bottom. Since the top is N, and the pole of the bar magnet nearer is also N, as like poles repel, the N of bar magnet will move away and rotate clockwise. The S of pole of the bar magnet will be attracted to the N at the top, hence likewise it will cause the bar magnet to rotate clockwise. Alternatively you can image the bar magnet to be like a compass needle, and the needle will follow the direction of the magnetic field with N of the needle pointing in the same direction of the magnetic field direction.