ECAT Physics MCQs

A vector has both magnitude and direction.
Acceleration describes the rate and direction of velocity change.

Both sides of a valid physical equation must have the same dimensions.
Dimensional analysis can reveal inconsistent formulas.

The newton is derived from base units as kg·m/s².
Metre, kilogram, and second are base units.

Precision describes repeatability.
Measurements can be precise without being accurate.

Accuracy describes agreement with the true or accepted value.
Systematic error can reduce accuracy.

Systematic errors often arise from calibration or method bias.
Repeated measurements do not automatically remove them.

Random errors cause scatter around a central value.
Repeated measurements and averaging can reduce their effect.

Leading zeros are not significant, but trailing zeros after a decimal are.
Thus 4, 5, and the final zero are significant.

Vector addition replaces multiple vectors with an equivalent single vector.
Its direction and magnitude depend on the original vectors.

Perpendicular vector components form a right triangle.
The resultant magnitude is found from the sum of squared components.

One kilometre equals 1,000 metres.
Therefore 3.5 km = 3.5×1,000 = 3,500 m.