Mechanical reasoning test with the working shown

Every item in this set is the same trade seen from a different angle: a simple machine cannot give you work you did not put in, so anything it makes easier it makes longer. Four rope sections under a load quarter the pull and quadruple the rope you haul. A lever arm three times the load’s needs a third of the force and moves three times as far to shift the load the same distance. A gear pair that turns four times slower turns four times harder, which is the whole content of a reduction gearbox. A piston three times the diameter gives nine times the force and moves a ninth as far, because its area is what the pressure acts on and area carries the square. Once you can see which quantity is being multiplied and which is paying for it, the arithmetic is division, and the five topics stop being five things to remember.

The reason a page like this is worth taking anyway is that knowing the rule and reading the drawing are separately learnable. That is one of the better-documented findings in physics education: Hestenes, Wells and Swackhamer’s Force Concept Inventory (1992, The Physics Teacher) showed that students who could pass a mechanics exam kept their pre-instruction intuitions about forces intact, and McCloskey’s work on intuitive physics (1983, Scientific American) catalogued how systematic those intuitions are — people predict a ball leaving a curved tube will keep curving. The oldest example is still the most startling: Piaget and Inhelder’s water-level task, in which adults are asked to draw the surface of the water in a tilted bottle and a substantial share draw it tilted with the bottle rather than horizontal. Vasta and Liben went back over three decades of that literature in 1996 (Current Directions in Psychological Science) and the puzzle they described is that the failure survives being told the answer. None of these figures is printed here as a score, because none of them was collected on these items — they are the reason the page shows working instead of just marking you.

Two things go wrong on practice material for this topic, and both are visible rather than arguable. The first is a diagram that could not physically work: gears drawn with mismatched tooth pitch, or a tackle whose rope path cannot be followed, teach a reading habit that fails the moment a real battery draws it properly — which is why a gear’s radius here is set by its tooth count and the rope is one continuous path. The second is a score with no derivation, which tells you that seven of twenty were wrong and leaves you no way to find out whether it was one missing rule or seven careless readings. The format itself has a caveat worth stating: the well-known pictorial batteries in this family, the Bennett Mechanical Comprehension Test among them, mostly ask for a comparison rather than a quantity, so asking for the number is a deliberate departure from that format in the direction of teaching. For the comparison format under a clock, take the mechanical aptitude drill instead. For the figural and rule-finding items that sit beside mechanics in most batteries, there is pattern recognition, the matrix format and deductive reasoning; for the numbers-in-a-table half of an industrial paper, numerical reasoning and the Watson-Glaser practice page cover what usually comes next.

A reaction time here is the interval between the frame that painted the stimulus and the timestamp the browser attached to your key, both read from the same monotonic clock. What neither can see is the display pipeline behind it, so on a 60 Hz screen roughly 16 ms of every figure below is the machine rather than you. That is the timing floor: two numbers closer together than that are the same number, and this page reports no precision it cannot support.

The only figures this page reports in time are per-topic medians of tens of seconds, and the floor above is four orders of magnitude below them. It is stated anyway, because the seconds recorded here come off the same clock the timed pages use, and because an item interrupted by the window losing focus is discarded for exactly that reason.

This is a measurement exercise, not a clinical assessment. It reports what you did on this page against a stated reference and nothing more — it cannot establish a mechanical or spatial difficulty. Only a qualified professional, working with more than a browser, can make that judgment.

Not affiliated with, endorsed by, or connected to Pearson Education, Inc.. Bennett Mechanical Comprehension Test is a trademark of its owner and is used here only to name the assessment this page prepares for. The questions on this page are our own: no part of the published test is reproduced, and a score here is not comparable to a score from the real instrument.