Pakistan MCQs

Move the decimal four places to the right to obtain 7.2.
Therefore the exponent is -4.

Use the Pythagorean theorem for perpendicular components.
Magnitude = √(3²+4²)=5.

The x-component is A cosθ.
10 cos60° = 10×0.5 = 5.

The y-component is A sinθ.
10 sin30° = 10×0.5 = 5.

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

Vectors in the same direction add directly.
The resultant is 12+7 = 19 N.

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

Opposite collinear vectors subtract in magnitude.
The resultant magnitude is |12-7| = 5 N.

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.

Their closing speed is 20 + 25 = 45 km/h.
Time = 90 ÷ 45 = 2 hours.