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Various options are provided as possible answers to the following questions - NSC Physical Sciences - Question 1 - 2018 - Paper 1
Question 1
Various options are provided as possible answers to the following questions. Choose the answer and write down only the letter (A–D) next to the question numbers (1.1... show full transcript
Worked Solution & Example Answer:Various options are provided as possible answers to the following questions - NSC Physical Sciences - Question 1 - 2018 - Paper 1
Step 1
1.1 The net (resultant) force acting on an object is equal to the ... of the object in the direction of the net force.
Answer
The net (resultant) force acting on an object is equal to the rate of change of momentum of the object. This is derived from Newton's second law of motion, which states that force is the time derivative of momentum.
Step 2
1.3 At which ONE of the positions indicated on the diagram will the magnitude of the momentum of the stone be the GREATEST? Ignore air resistance.
Answer
The magnitude of the momentum will be greatest at position III. At this position, the stone is at its highest velocity as it moves downwards, maximizing its momentum.
Step 3
1.6 Which ONE of the following is NOT an application of the Doppler effect?
Answer
C Detecting the heartbeat of a fetus using ultrasound is NOT an application of the Doppler effect. The Doppler effect applies to waves and their frequency shifts due to relative motion, while this option describes a diagnostic use without the necessity for such a shift.
Step 4
1.7 The magnitude of the electrostatic force which the spheres now exert on each other, in terms of F, is:
Answer
After touching, the charges on the spheres will redistribute equally as they are identical. Therefore, each sphere would have a charge of +q. The electrostatic force between them can be calculated using Coulomb's law, giving the new force as ( \frac{4}{3}F ).
Step 5
1.8 How do the readings on the ammeter and voltmeter change?
Answer
When switch S is closed, the ammeter reading increases because there is a complete circuit allowing current to flow, while the voltmeter reading decreases due to the internal resistance of the battery. This reflects the changing conditions in the circuit.
Step 6
1.9 In which ONE of the combinations below is CORRECT?
Answer
The correct answer is D (i), (ii) and (iii). All the factors listed affect the magnitude of the current induced in an AC generator. The number of turns, the strength of the magnetic field, and the speed of rotation all contribute to the induced current.
Step 7
1.10 Which ONE of the following represents the gradient of the graph?
Answer
The gradient of the graph represents Planck's constant (h). This is derived from the relationship between energy and wavelength in the photoelectric effect where the gradient corresponds to ( \frac{hc}{\lambda} ).