Newton's Laws of Motion

Question 1

What is Newton’s 1st law of motion?

Answer 1

If the forces acting on an object are balanced, the resultant force on the object is 0.

So:

• if it’s stationary, it stays stationary.
• if it’s moving, it moves at a constant speed.

Essentially it’s Inertia - the tendency of an object to stay at rest or move at a constant speed.

Question 2

What is Newton’s 2nd law of motion?

Answer 2

The acceleration of an object is directly proportional to the amount of force, but inversely proportional to the mass.

EQUATION : Force = mass x acceleration. F = m x a. (N) = (kg) x (m/s^2)

a = F / m

• bigger f = bigger a
• bigger m = smaller a

Question 3

What is Newton’s 3rd Law of Motion?

Answer 3

When 2 objects interact with eachother, they exert equal and opposite forces on each other.

The earth pulls us down.
We pull the earth up.