Ch. 13Lesson 3

What are Newton’s laws of motion?

net force• combination of all forces acting

on an object• determines whether an object will

start moving, stop moving, or change direction

equilibrium• state when in which all forces acting on an object are in balance

Newton’s laws of motion

Sir Isaac Newton

• objects at rest tend to remain at rest & objects in motion tend to stay in motion unless a net force acts on it

1st law of motion

inertia• tendency of an

object to resist any change in motion

examples of inertia1. quarter on elbow trick

(stationary object)

2. passenger in moving car moving forward when car stops (remain in motion)

passenger & luggage in moving car moving forward when car stops

(remain in motion)

2nd law of motion

•motion of an object changes only when some force acts on the object

acceleration•rate @ which velocity of an object changes over time

• A force must be applied to an object to make it start moving, stop moving, speed up, slow down, or change direction.

3rd law of motion• For every action force

there is an equal & opposite reaction force.

• Forces (action force & reaction force) always occur in pairs

2nd law of motion

•motion of an object changes only when some force acts on the object

• objects at rest tend to remain at rest & objects in motion tend to stay in motion unless a net force acts on it

1st law of motion

3rd law of motion• For every action force

there is an equal & opposite reaction force.

• Forces (action force & reaction force) always occur in pairs

1st law of motion

• inertia= tendency of an object to resist any change in motion

1st law of motion

2nd law of motion•Acceleration-rate @ which velocity of an object changes over time