Paper 3 · Kinematics and Dynamics
Which factor can make a dimensionally correct equation physically wrong?
AMismatched term dimensions
BBad dimensionless constant
CWritten using SI units
DMore than three variables
Explanation: A dimensionless constant carrying the wrong numerical value leaves every term's dimensions matching (so the equation still passes a dimensional check) while making the equation physically incorrect. Mismatched term dimensions would instead make the equation dimensionally inconsistent, not just physically wrong; the choice of unit system and the number of variables have no bearing on dimensional correctness.
Derived from ZIMSEC Physics Paper 3, June 2004, Q1