Pakistan MCQs

Angular velocity describes how fast and in which sense an object rotates.
Its SI unit is rad/s.

Conserve momentum: 2×6 = (2+4)v.
V=12/6 = 2 m/s.

Angular acceleration measures how quickly rotational speed changes.
Its SI unit is rad/s².

Total momentum is 3×4+1×2=14 kg·m/s.
Total mass is 4 kg, so v=3.5 m/s.

Moment of inertia depends on mass and its distribution about the axis.
Mass farther from the axis increases it.

Take initial velocity as +5 and final as -3.
|Δp|=|2(-3-5)|=16 kg·m/s.

A body in rotational equilibrium has no angular acceleration.
Clockwise and counterclockwise torques balance.

Torque is force times perpendicular distance.
τ=10×0.5 = 5 N·m.

Work is W=Fd when force and displacement are parallel.
W=20×5 = 100 J.

Use W=Fd cosθ.
W=10×4×cos60° = 20 J.

Kinetic energy is ½mv².
K=½×4×9 = 18 J.

K=½mv².
K=½×2×100 = 100 J.