NAT Physics MCQs

Net work equals the change in kinetic energy.
Kf=20+80 = 100 J.

Use a=F/m.
A=12/4 = 3 m/s².

All isolated collisions conserve momentum.
Elastic collisions also conserve total kinetic energy.

Centripetal force is mv²/r.
F=2×36/4 = 18 N.

The objects share a common final velocity.
Momentum is conserved, but kinetic energy is not.

Centripetal acceleration is v²/r.
A=100/20 = 5 m/s².

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

Acceleration is F/m = 4 m/s².
Change in velocity is at=4×3 = 12 m/s.

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

The net force is 80-20 = 60 N.
Acceleration is 60/15 = 4 m/s².

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

Constant velocity means zero acceleration and zero net force.
The normal force therefore equals the person's weight, 600 N.