This lesson is optional background, not a section of the HAT-1 paper. HAT-1 tests verbal, analytical and quantitative reasoning only; the orientation lesson is explicit that there is no technical section. The material is included because engineering and computing candidates often want their school-level physics refreshed before graduate study, and because a confident grasp of mechanics and electricity supports faster, less error-prone quantitative reasoning. Treat it as enrichment, not as revision for a paper that does not contain it.
The difficulty is not conceptual. It is that a test gives you about a minute per question, and formulae you last used years ago are not recalled in a minute. This lesson is about the small number of relations that cover most numerical questions, and about avoiding the unit errors that produce a plausible wrong answer.
Nearly every mechanics numerical follows this three-step pattern.
Step three is not bookkeeping. Mixing grams with kilograms or centimetres with metres is a common source of quantitative-reasoning errors, and the option set usually contains the mixed-unit value.
Kinematics for motion in a straight line with constant acceleration.
Pick the equation that omits the quantity you neither know nor need. In projectile questions, horizontal and vertical motion are treated independently: the horizontal velocity is constant, and the vertical motion is uniformly accelerated by gravity with g taken as 9.8 m/s², or 10 in questions that say so.
Newton's laws. The first says a body stays at rest or in uniform motion unless a resultant force acts. The second gives the quantitative relation.
The third says forces come in equal and opposite pairs acting on different bodies — and a favourite exam trap is a question about a horse pulling a cart or a person pushing a wall, where the pair being described acts on two separate objects and therefore cannot cancel for either one of them.
Work, energy and power.
Mechanical energy is conserved when only conservative forces act, which is the assumption behind most energy questions. Note that work done perpendicular to the motion is zero, so a force carrying an object horizontally does no work against gravity.
Momentum and impulse.
Momentum is conserved in collisions and explosions when external forces are negligible. Elastic collisions also conserve kinetic energy; inelastic ones do not, which is the distinction most collision questions are really testing.
Electricity, the other large area.
Units to keep straight. Force in newtons, energy and work in joules, power in watts, charge in coulombs, potential difference in volts, resistance in ohms, frequency in hertz. Prefixes are a common source of error: 1 kN is 1000 N, 1 mJ is 0.001 J, and 1 μm is 10⁻⁵ m.
A car starts from rest and accelerates uniformly at 2 m/s² for 5 seconds. How far does it travel?
List the givens: u = 0 (starting from rest), a = 2 m/s², t = 5 s. You are asked for s, and v is unknown and not required. The equation that contains u, a, t and s, and omits v, is s = ut + ½at².
Substituting: s = 0 × 5 + ½ × 2 × 25, which is 25 m.
Notice what the third step of the method would have caught. If the accelerations had been given in km/h² or the time in minutes, the substitution would have produced a number in the same magnitude but with the wrong unit, and the option set would very likely contain it. Converting first, and asking "is 25 in metres a sensible stopping distance for these inputs?", is what separates the correct option from the trap.
A car starting from rest accelerates at 2 m/s² for 5 s. What is its final velocity?
A force acts on a 4 kg mass and produces an acceleration of 3 m/s². What is the force?
A 12 V supply is connected across a 4 ohm resistor. What current flows?
Without looking back: which kinematics equation omits v, and what does the work-energy relation say about a force perpendicular to the displacement?
The answer is: s = ut + ½at²; and a perpendicular force does no work, because work depends on the component of force along the displacement, so cos 90° is zero.
Fill in the blanks from memory:
The SI unit of force is the , and the SI unit of power is the . Kinetic energy is given by one half times mass times .
Take five numerical questions from your intermediate physics paper and solve them using the three-step method: list the givens, choose the equation that omits the unwanted quantity, convert to SI before substituting.
Time yourself. The point of the exercise is not accuracy on untimed work, which you already have, but recall speed under a minute per question.
Keep a list of the mistakes you make, and expect them to cluster in two places. The first is unit conversion, particularly grams to kilograms and centimetres to metres. The second is choosing the wrong kinematics equation, which usually means a quantity you did not need was treated as known. Both are mechanical, and both disappear after a handful of repetitions.
Finally, write the formula down before substituting numbers. Candidates who substitute directly from the question tend to reach the options without a record of what they did, so when the answer is not among the options there is nothing to check. A written equation gives you a one-line audit.
Physics covers the mechanics questions. The next concept turns to computing, where a different set of basics is tested — number systems, logic and the fundamentals of how programs are structured.