Sanity Test

Which one of these examples, “makes sense”?

  • A- The acceleration is 9.8 m.
  • B- The acceleration is 9.8 \dfrac {m} {s}.
  • C- The acceleration is 9.8 \dfrac {m} {s^2}.

If you are sane, you should say that only “C” makes sense, as acceleration has units of distance per time squared.

Below is another example where we can use the sanity test:

  • A- Forensic experts at the scene calculate that the car was traveling 100 km/hour.
  • B- Forensic experts at the scene calculated that the car was traveling 10,000 km/hour.
  • C- Forensic experts at the scene calculated that the car was traveling 1,000,000 km/hr.

That one should be even easier–can you see that “B” and “C” can’t be possible?