Practice physics class test — Year 3: work, energy and collisions.
15 questions drawn at random from a bank of 25, on the block of the programme your teacher is finishing: every attempt is a different test. No penalty for wrong answers, so answer even if you are not sure. At the end you receive by email the correct answer to every question and your weak topics — with an account you see them straight away here on the page. The step-by-step solution unlocks with your first lesson.
A class test is the written test an Italian high-school class sits after each block of the programme; this practice version is multiple choice.
Test in ItalianThe questions of this simulator are in Italian, as in the real exam.
Programme covered by the test
- Work done by a constant force and power
- Kinetic energy and the work-energy theorem
- Gravitational and elastic potential energy
- Conservation of mechanical energy
- Work done by nonconservative forces (friction)
- Momentum and elastic and inelastic collisions
Two worked examples from the test
Una cassa viene trascinata per su un pavimento orizzontale da una forza costante di diretta nello stesso verso dello spostamento.
Quanto vale il lavoro compiuto da questa forza?
Solution
Forza e spostamento hanno la stessa direzione e lo stesso verso: l'angolo fra i due vettori è e quindi .
Il lavoro vale .
Attenzione: nella definizione di lavoro non compare nessun fattore (quello appartiene all'energia cinetica), e forza e spostamento vanno moltiplicati, non divisi né sommati.
Una slitta viene tirata per lungo un percorso orizzontale mediante una fune che forma un angolo di con l'orizzontale. La tensione della fune vale e si mantiene costante.
Quanto vale il lavoro compiuto dalla tensione della fune?
Solution
Solo la componente della forza lungo lo spostamento compie lavoro:
Con :
Errori tipici: dimenticare il coseno (si ottiene ), usare (si ottiene ), oppure fermarsi alla sola componente della forza, , che è una forza e non un lavoro.
In the online practice test you will find 13 more questions like these; the correct answer to every question arrives by email.
Prefer paper? Download the test as a PDF (15 questions, 4 pages · 78 KB, ready to print). You receive the solutions by email after taking it online.
Download the PDFWhat a physics test on work and energy looks like
The work done by a constant force, also at an angle, the work-energy theorem, a conservation of mechanical energy on a slide or a pendulum, a case with friction to treat with the work of nonconservative forces and an elastic or inelastic collision.
The mistake that costs the grade
Using the conservation of mechanical energy where there is friction. And, in inelastic collisions, applying the conservation of kinetic energy: there it is momentum that is conserved, kinetic energy is not — the difference is exactly what the problem asks you to calculate.
How to use this practice test
Take it once cold, without revising and with the timer on: it is there to show you where you stand, not to look good. Then look at your weak topics, revise only those — usually two or three, not the whole chapter — and retake it after a few days. The 15 questions are drawn from a bank of 25, so the second attempt is not the same test and the scores are genuinely comparable.
Is the score not enough?
See which topics lost you the most marks, then read the typical physics mistakes in high school — or we look at your results together: the diagnostic is free.