all about Newton's laws of motion

What does the 1st Law of Motion (Inertia) state?

A body stays at rest or in uniform motion unless a net force acts.

What is the equation for the 2nd Law of Motion?

F = m a (force equals mass times acceleration).

According to the 3rd Law of Motion, what happens to forces when one body exerts a force on another?

Forces come in pairs: equal magnitude, opposite direction, and same line.

What does it mean when ΣF = 0 in the context of inertia?

It means that the velocity (v) is constant.

In a Free-Body Diagram (FBD), what are the steps to properly isolate the body?

1. Isolate the body, 2. Draw all real forces acting on that body, 3. Choose axes, 4. Apply ΣF equations, 5. Solve algebra.

How is weight calculated in physics?

W = m g, where g ≈ 9.81 m s⁻² downward.

What does the normal force (N) adjust to do in physics?

It adjusts to prevent penetration into surfaces.

How does friction between surfaces behave in terms of static and kinetic friction?

Static friction is greater than kinetic friction (μₛ > μₖ).

What happens to the normal force when an elevator accelerates upward?

The normal force increases: N = m(g + a) → heavier.

What is the relationship between force and acceleration in circular motion?

Centripetal force is the resultant of real forces pointing to the center: ΣF_in = m v²/r.