ECAT MCQs

ΔK=½m(v²-u²).
With m=2, ΔK=49-9 = 40 J.

Momentum is p=mv.
P=6×4 = 24 kg·m/s.

Torque depends on force, lever arm, and angle.
It is the rotational counterpart of force.

Impulse equals change in momentum.
J=3(8-2)=18 N·s.

Torque magnitude equals force times perpendicular lever arm.
A larger moment arm produces greater turning effect.

Impulse is FΔt for constant force.
50×0.2 = 10 N·s.

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.