Question 1

What is Newton's Second Law?

Accepted Answer

Newton's Second Law states that force equals mass times acceleration: F = m × a. The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

Question 2

What are the units of force?

Accepted Answer

The SI unit of force is the newton (N), where 1 N = 1 kg·m/s². In imperial units force is measured in pounds-force (lbf), where 1 lbf ≈ 4.448 N.

Question 3

How do I calculate weight from mass?

Accepted Answer

Weight is the force of gravity on a mass: W = m × g, where g = 9.81 m/s² on Earth. A 10 kg object weighs about 98.1 N. Weight changes with gravity; mass does not.

Question 4

What is the difference between mass and weight?

Accepted Answer

Mass (kg) measures the amount of matter and is constant everywhere. Weight (N or lbf) is the gravitational force on that mass, so it changes with local gravity — you weigh about 1/6 as much on the Moon.