1. Seat Belts and Newton's First Law

When a car brakes suddenly, passengers continue moving forward (inertia). Seat belts apply a backward force (Newton's Second Law: F = ma) to decelerate the passenger safely. Without a belt, no force acts, and the passenger hits the dashboard — a direct consequence of the First Law.

2. Banked Roads and Highways

Highway curves are banked at angle θ where tan θ = $v^{2}$/(rg). At the design speed, no friction is needed, reducing tyre wear and preventing skidding. For speeds above or below the design speed, friction provides the supplementary centripetal force.

3. Rockets and Newton's Third Law

Rocket propulsion: exhaust gases are ejected backward (action); the rocket is pushed forward (reaction). Both forces are equal in magnitude but act on different bodies — exhaust and rocket respectively. This works in vacuum where no air is needed to "push against."

4. Weighing Scales in Elevators

A spring weighing machine in a lift reads apparent weight W' = m(g ± a), not true weight mg. This is why you feel heavier in an accelerating elevator and lighter when it decelerates. Astronauts in orbit are in continuous free fall — their apparent weight is zero (weightlessness).

5. Anti-lock Braking Systems (ABS)

ABS prevents wheels from locking (sliding) so the tyre operates under static friction (larger μ_s) rather than kinetic friction (smaller μ_k). Since μ_s > μ_k, maximum braking force is higher, stopping distance is shorter, and steering control is maintained.

6. Washing Machine Spin Cycle

The spinning drum provides centripetal force to the wet clothes. Water, being less constrained, cannot receive sufficient centripetal force and exits through the drum holes — exploiting the difference between what receives centripetal force and what doesn't.